Congratulations on getting your first pointe shoes, it's such an exciting thing. I just got mine 8 months ago. :)
Pointe shoes and their accessories all vary in price depending on brand and styles. You should expect to pay at least $100 though. My pointe shoes were $82 and overall I spent $110 on those along with ribbons, elastic and toe pads. I know many brands of shoes range from around 50-90 dollars.
There is no "perfect padding" out there that will work for everyone. Each dancer has her own shape of foot and pain tolerance, no one is the same. You'll have to go with whatever padding you're most comfortable with. The goal is to preferably have as little padding as possible to feel the floor, so don't be afraid to try just plain lambswool with toe tape along with your toe pads, and other accessories needed for your feet. Who knows, the lambswool may work best or it may be the toe pads!
For your fitting, you should wear a pair of convertible tights and a leotard or a top with shorts or pants you can roll above the knee. A top with shorts or a leotard are most conveniant however as pants can most often fall down again and get in the way. (I know as I got fitted when it was probably 20 degrees out and HAD to wear pants... didn't think of bringing shorts or my leotard either. >.<)
You'll try on many different styles of Russian Pointe shoes and go see which one works best. You'll usually be asked to plie in them, and stand en pointe at a barre to make sure you're comfortable in them and can get over the box at least fairly well for not having them broken in.
Don't be afraid to ask the fitter questions either. You want this to be a good experience for you and your first pair of shoes! You don't want to go home with the wrong pair and be in agony wearing them to class until they either die, or you're forced to replace them.
Hope I helped! :)