There are 2 types of collectors: those who have at one time or another, overpaid for an item; and liars.
Personally, the regrets I harbour for paying too much for a record are far outweighed by the much more potent pain of not buying records I which, at the time, I considered to be overpriced due to the possibility that a few boxes were lurking undeclared somewhere, just waiting to be sprung on unsuspecting dupes - like me. In the pre-social media days this was a serious risk.
As Bosshoss intimates in the previous post, take a long term view. Unless it's more than 25 copies, a sudden 'quantity' find will only deflate prices for a relatively short period. Then, with demand and the appearance of new collectors, the price will probably rise again. It may take 20 years but, if you are not too long in the tooth and you are in it for the long haul, the wait is well worthwhile.