Ok now I have a crappy 15w peavey vypyr Im getting a Blackstar 5w head but I was wondering If I could get a 4x12 instead of the 1x12 that comes in the mini stack version. If so whats the best I can get for 300 or less because thats all I will have left after the head. The reason I need a bigger one is because I'll be gigging.
you can do that ...but I'd focus on a 212 cab and match the ohms to the HT head and match the watts as closely as you can. A 200 watt 412 cab may not work so well tone wise with a 5 watt amp but I'm not a cab expert.
what would a good 2x12 be for around 300? To be honest that would probably be alot more practical for me anyways.
Use the link in my sig or search on your craigslist for 'cab' or '212 cab' by Mesa, Orange, Avatar, Vadar, Carvin, and Marshall.

I'm sure you'll find something that matches up well. New Avatar 212 cabs are $400. I like the Avatars.