Got rid of a 642CT for a 520. Added $35.00 to the trade.

I got the 642 on trade for a watch that I no longer wore, so...I can't put much of a value on the 642.

I looked on Gunbroker, and the only one listed is over $850. Did I do that well?

That one 520 listed on GB for 850 has been on there for a very long time. PC guns go for 850 and sometimes a little less and are much more revolver then a stock 520. However, the 520 is relatively rare although they may not be very sought after. I for one would love to have one, as well as quite a few other things.

Something is only worth what someone else will pay for it, not what someone says it is worth... free market rules.