check out this:
http://www.ehow.com/how_4489425_properly-house-betta.html
now, make sure the tank is at least 2.5gallons, has a filter and a heater.
can you get snails? sure if you want. some bettas kill them, some don't. what I'd suggest is the "pest snails" that are on he plants in pet stores. they'll give them to you free. however, understand that having snails does NOT mean you don't have to clean your tank. EVERY tank needs a weekly water change between 10% and 25%.... give or take some depending on the fish. for your tank anywhere in that range is fine.
you'll need:
tank
gravel
decor (silk or live plants... live java fern would be nice and it probably come with some free snails)
net
water conditioner
food
filter
heater
thermometer
gravel vacuum (use this for weekly water changes)
that's about it... feed everyday 3-6 pellets a day. skip one day a week. bloodworms, brine shrimp, and daphnia are good treats a few times a week. change 10% to 25% of the water once a week using the gravel vacuum and you'll have a very happy betta.
also, bettas do NOT like small tanks... if you can afford and have room for a larger tank, I'd suggest getting one. they're easier to keep. also if it's at least 10gallons you can have more tankmates if you wish.