The PA880 is decent. But I got mine BNIB for $140. Then sold it to my brother for $150. Haha.
I went in blind. A friend I knew was like "I wanna sell my amps and sub" after she bought a used Acura CL. She was asking for $200, ended up talking her down to $170. Didn't even know what I was getting. I ended up getting a Diamond D3 400.4, 800.1, a D3 12D4 sub in a custom sealed box, and a Monster 1 farad cap. Gotta say, I pretty much ripped her off. Haha.