Quote from MusicScout >>

I might have the official take a look at the mammoths and reply, "Well, to be frank, I don't think we can afford to pay you for the weight of these monsters.  If you want to start bringing it in we'll have to talk to the (Mayor) about how much we can afford to give you.  You know, we were really thinking wolves, badgers and foxes when we wrote that ordinance.  This, well, this is a whole 'nother matter."

And then you could offer to give them a lump sum of gold and one magic item, and the town takes responsibility for retrieving the animals. 

I like this response. 

My suggestion is: give them what you promised them when setting up the quest. They may be too powerful for a while but as they level up the encounters will begin to challenge them again.

24,000 gp is the equivalent to 46 years of (5 days per 7 day week) work of a skilled 5e worker or 460 days work of an unskilled worker.  
Beyond effects on players, it could bankrupt many types of town that might be in near vicinity to woods.  Is this something you'd like to RP through?

You could make it a plot point - the deperate mayor takes the money as a loan from a stranger who has head his plight and wants to help. The gold belongs to a dragon, who is now hunting the party, and will give them a chance to make the money up and give it back to them - let them spend it for a bit, then give them a "you have 2 weeks to get my money, or you're dead" plotline. I think that combines al lthe fun - the players get to first spend the money, then they have to earn/steal the money fairly, putting the work in afterwards, and the plot advances. If they return to the town, they find it a blackened ruin from the dragon's wrath.

Or the mayor (not so desperate) might just have exactly the same reaction as the DM (essentially the same person), "shit, I didn't plan for the possibility that the party would kill mammoths".  Sorry, we can't pay up to that.  

Basically, a town leader would be set for the stocks for agreeing to give away a considerable amount of town's funds/get the town into considerable debt. 

Essentially you can come up with a scenario where the town just has a limited amount of money.  The party can approach that however they want but there could be implications.  

Meat beyond a certain quantity would be worthless as it would go off.  They'd only want to buy the amount of meat needed for the feastival.

DId the party ask to read the small print of the hunt competition?  If not you can retcon that small print to read how you like.

I'm sorta liking the party holding the town to the absurd prize purse, like constantly shaking down the town for what they're owed and not stopping harassing the town till they get their 24k gp in full.  People often wonder how an evil campaign can work, here we go.  And then another party comes to save the town from these oppressors, to the tune of 100 gold.

I would let them have the gold and then find ways to get them to spend it (hiring equipment to get the mammoths back to town is a good one, the town are not going to give that for free). Remember as well gold is an encumbrance, how will they carry it all? also towns folk will know they have money, suddenly price of lodging will go up etc 

What size is the settlement? How rich are the festival organizers? They might just not have enought money for such a big kill. If it was my game, there would be a limit of 2500 gp, a reasonable sum for a party L4. 

Without magic support, a mammoth of that weight has no mundane cart capable of carrying it, or mount capable of dragging it on the ground effectively. If you opt for 24000 gp, the beast would have to be cut and carried over many carts doing back and forth and would require payment to cover expanses of butchery, cart, driver and mount. It could easily cost them a few thousands. 

Another factor, I just looked and you only get about 63% of the weight from a carcass as usable meat from say a cow.  Imagine that mammoth is not something they readily know how to butcher well and just round that down to 50%.  You just greatly reduced your payout through logic.

A draft horse, according to the rules, can pull 2700 pounds. A wagon is 400 pounds, so a draft horse with a wagon can pull 2300 pounds. They would need 11 wagons pulled by horses, or of you can put multiple animals in front of a wagon, something like 2 wagons pulled by 4 horses each. 

That said, I highly recommend not nerfing their winnings too much. That would just be frustrating. Unless you offer a magic shop (not recommended in 5e), there really isn't all that much to do with money that would break the game.

Alternative suggestion: *Roleplay the mistake*!

It wasn't your mistake. It was the town's mistake. The town is now shocked that they have to pay such a high prize! Your heroes broke the bank! Turn it into a story! Maybe the town now tries to murder them. Or they beg for forgiveness because paying the prize would mean ecomomic downfall of the town! Maybe they can pay half and give the rest of the value as in IOU or some magic item of your choice. Or they offer information instead of gold.

Another cheap solution would be for the organizers to rely partially on Fools Gold ☺

Quote from Sanvael >>

There is also the following logistical question:

How do you get a dead mammoth onto a wagon? Unless you can shrink it, I just don't think it's feasible. The PCs would need some form of magic to move them at all, otherwise they need to cut the mammoths into pieces.

Where do you find a wagon that can take the weight of a mammoth? Standard wagons won't take that kind of weight. They're made out of wood, and intended for some agricultural produce or a few passengers.

Overall, I'd say that it's not feasible to transport a mammoth.

 Furthermore, because folks could use enlarge/reduce to cheat and get more money, perhaps there could be a regulation against magically tampered-with meat.

Quote from NommerstheHero >>

I am a first-time DM and I have homebrewed a campaign. In my last session, I had a sort of hunting festival. Party members were given a chance to go out into the woods and hunt down animals. When they brought them back to the city, they would be paid 1 gold per pound. I made 3 rings in the forest and my players went into the most dangerous ring. After doing some rolls, their encounter was with some mammoths. I didn't think of it much at the time but my players managed to kill the mammoths and they are now taking a long rest before heading back to get their gold. They plan to have one person run back to grab an official with some wagons. Then hauling back the mammoth meat. However, I didn't realize that mammoths weighed a **** ton and will give the party 24,000 gold for it all! They are only a level 4 party and there are 6 members. So this would equal to 4,000 gold per person. That is far too much far too soon. I was thinking about compensating with some homebrew items I made but realized these items are considered a rare level. Too powerful for the party just yet. And they just turned level 4 so I can't quite justify it quite yet. These homebrew items are a plot point but again, it's too soon so I can't use them quite yet. How do I justly give my players all of the reward money without it seeming I am railroading or 'punishing' them for a mistake I made?

 I just think it's funny that you think its an unheard of mistake and that it would be rude to railroad the players. Spoiler alert

Quote from dermaniac2 >>

A draft horse, according to the rules, can pull 2700 pounds. A wagon is 400 pounds, so a draft horse with a wagon can pull 2300 pounds. They would need 11 wagons pulled by horses, or of you can put multiple animals in front of a wagon, something like 2 wagons pulled by 4 horses each. 

That said, I highly recommend not nerfing their winnings too much. That would just be frustrating. Unless you offer a magic shop (not recommended in 5e), there really isn't all that much to do with money that would break the game.

 

 

 I will say I have a magic shop, in fact I have many I use the realistic price guide and magic items now become large money sinks.