There was a place in Tom’s River right off of 37 that was good.
I doubt they’re around anymore though.
What do you have? Much pre-WWI stuff? Real money is the Colombian exposition series and older as I recall.
The post office used to sell a color guide to all the stamps, might be worth getting one from your library and seeing what you have. Or even search some of the stamps on eBay to see what values they are commanding.