You also might want to look at PA gear. If you already have a mixer you can get a good power amp and one or two PA speakers. Then you can use it for vocals, guitar or anything and you wont be limited to just having a keyboard amp.
can you guys recommend anything in the 250-300 range, i just need it for jamming live with band in the garage before actually recording songs, i like the PA idea cause we can use it for vocals etc
Thats pretty cheap. For that you might be able to score a used QSC amp and a yamaha or peavey speaker. Good PA speakers from EV or JBL usually start about $600 new. You can get a mediocre PA system for around a $1000.
I noticed www.musiciansfriend.com as a Roland KC 100 keyboard amp for $269. For your budget you can get more in a keyboard amp then you will a PA system. If you can save up, though, the PA system will give you more flexiblity.