Some of the ones on ebay can be of high quality, even the ones down in the $25 range, you just have to read and know what to look for.
Careful with some of the stuff on Craigslist :-) , I've begun seeing relabeled HF and Cummins panels and "kits" being sold for more than you could buy them at both places.
Since you will be working with 12V sized stuff, the panel Vmp you should be looking at are the sub 22Vmp area. You certainly can go higher, but you can run into problems with controllers letting out majick smoke.
Also, Marine batteries>> If you have them or they come free to very cheap, or just want to learn on them, its okay.
They really aren't true deep cycle batteries like you would think. There are hybrid ones, but I've not used them so I can't really say if they're any better than grabbing some 6V golf cart batteries.
A neighbor set his system with two of them from Sam's and has been using them with his dual HF 45 watt system for 3 years now. He keeps a 1000 watt inverter connected (NOT turned on) in case they loose power OR he's hosting a party that goes into the weeeee hours.