new here and to raw

Hi, my name is sarah. i have 1 kitty whose name is Sully. He is about 3 yrs old and is about 7-9 lbs. I have been having problems with him vomiting all over the place and frequently. he is healthy just is doing that and i am about to go insane. i started hearing about raw diets and now am wondering about it. i would prefer to do the whole prey, but i dont know where to get them, what kind to get (rats, mice, chicks, etc.) and how many he would need a day. I need to have an idea so i can figure out the money aspect. he is an awesome mouser, just caught one this morning, but i know he can't survive on 1 mouse every yr or so lol. i basically need raw whole prey diet 101! Help would be GREATLY appreciated! thanks