>>11862625
You stick around in the community long enough, you get to know the prices. For me, it's coins. I've been doing it nearly my whole life, I always know a good price when I see one, and with rare exceptions I wait for instances with good prices rather than impulse buying.
General tips I've gotten from coins
>find a reliable store in your area that has good prices and honest merchandise (if possible, you could be in the panhandle of Oklahoma or something similarly rural for all I know)
>use ebay with caution, make sure the seller accepts return, check feedback, and to get a sense of prices, routinely check sold listing prices
>know how to negotiate and try your best to get up to 25% off if you really play your cards right
>don't even give the "I KNOW WHAT I HAVE" boomers the time of day, keep walking