For your first tank I would reccomend glass. Go for one of those top fin kits that petsmart sell as they will provide you with some of the basic stuff you need to get started. They will provide you with:
1 Glass Aquarium
1 Hood with lighting
1 Net
1 Filter (Labeled as a Top Fin but actually is a whisper)
1 Sample of Stress Coat + Stress Zyme (I don't use either of them but you can if you want)
1 Food Sample
1 Heater For Tropical Kit (Go for the Goldfish One and buy a visitherm heater instead if you want tropicals as it will save you a major hassle later on)
You will need to buy an aquarium stand, gravel (If you want but don't spread it more than 1/4" thick for your first tank), some sort of test kit. I like the aquarium pharm master test kit, decorations (ie: Plastic Plants), dechlorinator, correct type of food for the fish you want (tropical or goldfish), a thermometer, a box of aquarium salt.
Take all this home and wash the tank out very well (no soap or detergents). Once you think it is clean wash it again and set it up. Fill it up with water and add dechlorinator. If you want to go tropical, set the heater (I keep mine at 77*) and get the filter running. Start reading up on cycling the tank and types of fish you want to keep paying attention to size and compatibility. I reccomend that you do a fishless cycle. Even though waiting for maybe 3 weeks without fish is going to be tough, it will give you more time for research to make an educated decision and be less tough on your fish when you get them. One benefit is that you could fully stock your tank in one shot when you are done with the fishless cycle. Good luck with your new tank.