cool... don't get carried away and buy a 10 gallon tank just to see your fish die.
keep it in that bowl for a couple of months until you are use to it then upgrade to a bigger bowl. You dont need a 10 gallon. believe me. I have three betta. One half moon. One fighter. And a regular one. Speaking of the regular one... let me go check on him... i totally forgot about him.

 

and keep the bowl covered. One of my giant betta jumped out and dried to death

 

ive had my betta in a small bowl for like.. 7 months. im planning on getting the 12gal and putting him in there by himself until the tank cycles and then adding more fish slowly.. im planning on doing what supapoopa suggested.

the end result will be...

2 platies, 6-7 tetras and an algae eater, along with my one male betta.

see any problems with that?