Actually, I have no exact information, but I know that there are several "repeat" registrants from Korea (basically), China and Brazil that bombard the WHOIS servers with registration requests for domains that are about to expire. Let's not forget that the same is being done by SpanNames, ExpireFish etc.
I cannot claim I have registered domains this way; they always have expired first.
semms like they for about $10 on ebay, though obviously if someone contacted you you could fetch $500 or more. Really though there is simply no shortage of those kinds of names, hence very low selling prices.