I'll be getting from from Petsmart,is that an ok place to get one?
Yup, especially since you're just starting out. Just make sure you get an active-ish one that has very little or no fin damage (rips, tears, etc) and is probably flaring at you.
What kind tank do i need?
They need atleast one gallon, but since this is your only betta I highly recommend This if your petsmart happens to have them. If not, a good 1 gallon or a 2.5 gallon would be fabby .
I dont think they need a filter,they need plants right? What kind plants?
You don't need a filter unless you want one. They're not required and if you do get one, put it on the lowest setting. Plants aren't required, but they're nice to have. If you want fake, I recommend silk plants so they won't tear your bettas fins, but if you want live, Java ferns are some of a betta's faves.
What kind food do you recommend? (that you can get from petsmart)
Hikari Betta Biogold Pellets, or some Frozen bloodworms or live ones. Bloodworms are not required, and you may just want to start your guy out on pellets. Any will do, but Hikari is the best.
How often do i clean the tank?
If you have a 1 gallon, 1-2 times a week. If you have a bigger tank, once a week should do if you don't use a filter.
Water needs to be room temperature? From bottled water or just tap water?
Room temperature is okay, but if you get more than a 1 gallon, purchasing a small heater might be a good idea. If the room your betta will be staying in is pretty warm, it should be okay. If you use bottled, it must be spring water. Don't use distilled water. If you use tap water it absolutely MUST be treated with water conditioner. A good water conditioner is Novaqua +. I use it without Amquel +, and it does fine, but it is a bit on the pricey side, and it lasts me (with 8 bettas) a loooong time.

Hope I helped, and if you have any more questions, feel free to PM me or ask!