[nedorama]

used:

Peavey KB300, Roland's larger keyboard amp - sound great, and for the weight get a hand truck.

Or, just get a used Mackie SRM450 powered speaker - you only need one and they sound good, are 45 lbs., and you can have them on the floor laying down tilted up, or get a stand and mount it to get the sound up in the air. I have 3 in my band and we use 2 as floor monitors and our keyboard player uses one on a stand as his keyboard amp.

New, the QSC K-series are light, powerful and sound good. I'd get the K12 and not the K10 or K8 for keyboard. the K Series have a built-in mixer, which is a plus - one less thing to plug in and setup.

Avoid Behringer like the plague - their stuff is poor quality ripoffs of other people's designs and will break - with no music stores around, definitely not an area to save money on.

Good luck!