I would just buy new blem from REOsmods. Brand new blems are $115. REOs are nearly indestructible if properly cared for. The problem is some users abuse them and don't adhere to the same standard of cleanliness as most people and they get nasty internally with careless juice spills etc...
Because its juice feed, it's different than buying a tube / battery sort of mod. People's flavors can also be a challenge to remove I hear.
Stick with new blems (or new perfects) unless you personally know the seller. The blems are supposed to have minor cosmetic blemishes. In the 7 I've bought, I only saw anything I'd consider an imperfection on 1.
Oh and here's some more of my REO porn