I bought a pallet of subwoofers local once off ebay.... most just needed minor repair and I was able to salvage a bunch of them. Most I just plugged into the electrical socket //content.invisioncic.com/y282845/emoticons/crazy.gif.c13912c32de98515d3142759a824dae7.gif
I have bought from them before never more than 10, And I got lucky with about 50% working. Most would have a blown channel here and there. But over all wasnt bad.
Most places dont restock them after a return they send em out!
The biggest reason for a return is a bad amp. I remember reading a feedback from one of these that out of all the amps only 2 actually worked. The rest were junk. HDA is a good place but you have to use a little sense when buying.