So uh....title says it all really. I feel really bad and we have our second session coming up. We brought her dead body back to the town so I would really like to try to find someone to resurrect her if possible. Is this a thing we can try and how could we go about this?

There are spells called Raise Dead and Resurrection that can do it. You need a high level cleric to cast them. Perhaps the town has a temple run by a cleric high enough level to do it? That will depend on world, setting, etc.

Thank you so much! Hopefully the town has a cleric, we didn't do a whole lot of sightseeing around town before we left for our first mission lol.

Raise Dead is a 5th level spell, which you'd need a minimum level 9 cleric to perform. It also consumes a 500 gp diamond so you'd need to be potentially prepared to pay at least 500 gp to a level 9 cleric to do this for you, since you can't expect the NPC to eat the cost of the spell.

I can say that in my world, you'd have no hope in most cases. Only the head cleric of the entire order for a god might be high enough to cast Raise Dead. Typical "town" clerics would only be 4th or 5th level.

I'm hoping you killed a player character and not a player...

That said, it's all up to the DM. Like BW mentioned, it's quite expensive to have someone raised and, depending on the setting, clerics might have some restrictions on doing it. In any way it's going to cost you. If you don't have the cash you can always volounteer your services to the temple of the cleric which would allow for more quests.

Don’t feel too bad. Killing characters sucks for everyone, but it’s meant to: death in real life sucks too. Without danger of death, there’s no excitement in the game, and if you make cheating death easy, your players will get bored. Believe it or not, it’s essential for players to have fun. I killed one of my players’ characters in her first ever session, and she still enjoys D&D today!

My character was killed at low level and the DM had me raised at a temple but it was The Godfather scenario. We will call upon you to perform a service…That and because I was killed by spiders I had to make a wisdom save or panic and run if we fought an insect kinda thing or spider. Good RP opportunities both ways. 

And always remember the golden rule of D&D (as presented by me)...

If you are a smart DM, nothing in the game is truly "accidental"... ;)

I'm puzzled.  OP makes it sound like they were another player, but people are acting like they were the GM?

Did you kill the player or their character? If you killed the player then you should go get a lawyer, explain the situation and turn yourself into the police. If you killed a character then follow the advice given by others. (Remember, the player is not the character, and vice versa.)

Quote from 6thLyranGuard >>

I'm puzzled.  OP makes it sound like they were another player, but people are acting like they were the GM?

 Wait, you might be right. OP?

I agree, the OP's position is ambiguous so I have given sort of half-a-loaf answers.

Quote from BioWizard >>

I agree, the OP's position is ambiguous so I have given sort of half-a-loaf answers.

 Better than no-loaf like I gave. 😜

If you are the GM, you can always handwave things and have her be resurrected. The NPC can be anyone: a cleric from a temple, scholars from magical research organization, a veteran adventurer with a soft spot for noob adventurers, a devil from the Nine Hells. The price can be anything from free to having their soul being damned for eternity. Do whatever is convenient for you.

If you are a player, assuming the campaign is in a stereotypical fantasy world, as others have said, your best bet in session is to probably contact the closest temple. Out of session, you can also just ask your GM what you should do.

Quote from BioWizard >>

I agree, the OP's position is ambiguous so I have given sort of half-a-loaf answers.

Maybe it's just me, but I kind of got the impression the OP was a fellow player.

Sure. It's fixable. Heck, everything's fixable.

Two campaigns ago this exact thing happened to me. Very first session of a brand new campaign we're heading down an alley on some heist job, and my dragonborn sorcerer was clearly more perturbed with how dirty the alley was than with looking for bad guys, so I got ganked by a halfling assassin laying in wait for us. Luckily the rest of the party got the job done and dragged my scaly butt back to the guy who gave us the job. Next thing I know I'm waking up. Turns out the Zhentarim used a Raise Dead scroll on me. But! But... to repay that scroll we pretty much had to work for the Zhentarim for most of the rest of the campaign.

So it turned out pretty good, actually. You see, we all got a great chance to roleplay our characters, and the DM was basically just handed a clear motivation for us to all keep working together and an unlimited source of jobs to throw at us. 

If your party is a bit more "good" than we were, then maybe some temple offers to Raise the fallen character, in exchange for some work they need the party to help them with. Just roll with it. See where it goes. Everything's fixable.