Don't be nervous - that's why they invented Xanax. If your really stressed out about it, they will prescribe you a few before the sugery. You shouldn't feel much during surgery but pressure if it's simple, and if you need to go to an OS to have them out then they may give you gas or put you nite-nite.
The cost depends on who's doing it - a simple extraction at you reg dentist will be cheaper than an OS.
So that leads us to how difficult they will be to get out:
The pain (afterpain) will really depend on this. If it's simple, it really shouldn't be that bad. Swelling peaks 24 hrs later, that's when it's at it's worst.
For more difficult teeth, they may have to 'bang you up' a bit to get them out. You'll be asleep more than likely for that, so no issue there. But sometimes you can still ache in those areas for up to two weeks later. Sometimes you will have no issues at all and heal nicely.

It's all a roll of the dice, everyone is different. People tolerate pain differently.
Just take care of yourself after it's all over, and it's nice to have someone take care of you, too! Follow all instructions given, and you'll be fine
I want to give you a big ole hug

cause it's the apprehension that's the worst part. It's better to know now what to expect.