Where can I check an address to see if it has any clams or any other fork coins?
Just enter the address to check it here.
https://freebitcoins.com/clamchecker/dig/That site will buy your address for BTC, but if you go back to my post on the first page of this thread you will find how to dig them yourself and save the service fee of 1.10545574 CLAM per dig.
As for forked coins just go to a block explorer for the coin and search for your addresses.
I think it highly unlikely that the OP will be buying any addresses that have already had their bounties claimed and as already pointed the addresses he will buy are worth a lot more than $5.