- any police trade in S&W, Glock, Beretta, SIG-Sauer, (etc), autoloader
- any police trade in S&W .38 or .357 or revolver
for a used "civilian" gun, I'd go looking for a used Ruger P95 or P97, they are cheap new, cheaper still used, and very very reliable, and being Rugers they will last a lifetime or more... and if I was looking for a cheap reliable "civilian" used revolver, I'd search the gunshows and used gun counters for a decent Ruger Security Six, Speed Six, SP101 or GP100.
Rugers have always impressed me with their ruggedness, reliability and low price. I'd recommend them to anyone on a budget. They wont impress any gun "snobs" with the Ruger name, fancy doodads, pretty finishes or trigger smoothness, but they have an amazing tendency to go bang every single time you pull that trigger... with such low failure rates that even big name guns costing 2 or 3 times as much are envious.