First, welcome to the forum.
A lot of people (myself included) feed New Life Spectrum (NLS). Tiny pellets and easy to feed. Most discourage the use of flakes. Most Wal-Mart foods aren't as nutritious as NLS. You can also get frozen bloodworms as a "treat" for once a week.
A two gallon is fine but if you can afford to get something bigger and have room, a 5-gallon would be perfect. Wal-Mart has a couple of 5-gallon tanks that have everything except the heater for around $25.00. If the your store doesn't have them, I think it's only a one-day store delivery.
You will also need something that detoxifies ammonia (I use Prime) and either an API Master test kit or individual liquid testers for ammonia, nitrite and nitrate. You could buy 6-in-1 test strips but those aren't as accurate and you need accurate readings.
Read the stickies on tank cycling so you understand what's happening to your tank and why you need to keep a close check on the ammonia, nitrites and nitrates.
Hope this helps.