How much would something like this cost?

Using the rules for consumable common magic items, it'd range to cost 25 gold pieces to create and can be sold for at least 50 gold pieces. However giving the cost of rations on their own, this seems way too expensive, so you can probably argue that you can make/buy a jar's worth of them for the same price. Depends on you / your DM.

What's their weight?

Correction; common items cost 50-100 GP at market. Consumable items cost half that due to their limited use nature. Therefore, these beads would have a price in the neighborhood of 25-50gp each. Tho I honestly price mine at ~15gp each (sold in packs of like 3 or 5, so 45-75/pack) for the same reason you mentioned; the only benefit to these over good ol' trail rations is that these don't weigh 1lb each.

RAW, there's no weight listed, so they don't count towards your max carrying capacity.

Realistically, I'd say they weigh a couple ounces, or about as much as a single Orbeez bead

Underrated Item, Food that takes a second to eat provides complete nourishment never goes bad, and can be stored extremely easy. If you have a long campaign in a harsh environment or somewhere extra planar they are a godsend. 

Quote from HeskLongtail >>

Underrated Item, Food that takes a second to eat provides complete nourishment never goes bad, and can be stored extremely easy. If you have a long campaign in a harsh environment or somewhere extra planar they are a godsend. 

 
As long as you can also summon water.

https://www.dndbeyond.com/magic-items/bead-of-refreshment

How convenient. 

So what I'm understanding about this is if you are an artificer you can create this using an infusion so that during your downtime days you always have a source of food as you can just create another one or even you take your first rest make one, eat it then take another rest and you don't need to worry about making it again as you've already eaten enough for the day... what is the opinion on this thought process?

Because it doesn’t say one way or another, my interpretation is that regardless of a creature’s size, it will feed it for a day.

Toss a jar of 250 into the mouth of an ancient dragon and it will die from vitamin overdose.

Quote from Zethras_the_Worldforger >>

Because it doesn’t say one way or another, my interpretation is that regardless of a creature’s size, it will feed it for a day.

Toss a jar of 250 into the mouth of an ancient dragon and it will die from vitamin overdose.

 How to tame the tarrasqe. He is just hungry. Give him this to tame him

this one is free but the bead of refreshment is in the 2024 dmg XD

The "Consumable" keyword needs to be added to this item in the Magic Items database.

We are starting a campagin, and my Artificer/Gunslinger has this Infusion, for the campagin we are about to start, frontier exploration and colonization. I will never starve here in our winter camp. 😁

I can do more with Goodberry