GT Distributors has a fair number of Model 64 trade-ins on Gunbroker right now. It's possible to snag one to be chopped and still be at or under that $750 mark depending on what you want done.
Below is one of their 64-5s that I got last week. It's going off to Pinnacle High Performance to be converted to a trainer for the Model 13. Finish is about what I expected but timing and bore are excellent. Trigger is surprisingly heavy compared to the Model 13, I'll be adding a trigger job to the list.
Man, I'm really tempted to get another 64 as a trainer. At the price difference I might modify some RB ahrends.
I've lost several GB auctions by $5 or $10. But the thing is, you don't know what that other person was willing to pay. They may have been willing to go another $100. Just tell yourself it's probably their dream gun that they've been saving for for months and you did them a solid by not driving the price up.
Decide what you're willing to pay, bid that and ignore the auction until it's over.
I did the Ebay thing for a while. It is an emotional thing when bidding for an item......even more so when one loses by a few bucks. I too set bidding limits and let fate take over from there. But limits only work when one abides by them. I use to say to myself, "It's only a few bucks more" to justify going over my set limit. Like said above, you don't know who you are bidding against, but I went up with some screen names that I recognized from previous bidding wars. It is hard to divorce from an item that you really want, at least that's my experience.