All of those are great place to start. The big stores so you can test drive them. Then CL and Ebay to find the deal. You may be able to talk a store into a discount. Especially if it is being discontinued, or the box looks rough, as if it has been sitting in the store a while.
I got lucky with our lights. I found a DJ on CL that was upgrading his equipment. I bought all of his 64 par can LEDs (12 in all and DMX controlled) for like $500-600. There were other things in the purchase too, so I'm spit balling a little. They had some wear, but it was better than spending $150 for a single new light. We also bought a light truss from another guy on CL used for around $100. This one is very sturdy and runs for around 250 new I think.
The only issue now is the DMX controller. The DJ didn't come off his, so were running without one. The variation in color transitions is still quite nice and well worth the money.