The going price for average demand used CDs at the only remaining local B&M record/CD shop that deals with them is $6-$7 max. "Budget Bin" titles go for as little as $1.00 up to about $5. Rare still in demand hard to find titles (mostly imports) get more.
Used prices you can get on ebay tend to reflect this I find as well however shipping costs typically $3 postal media rate per CD must be factored in lowering the actual sale price accordingly.
It can be time consuming to maximize the value of selling $1000 CDs . The best approach is to identify any high value CDs up front and sell those individually, then sell the rest in multiple lots at auction as best as possible to keep shipping costs low. But even then, you have to take the time to list our details of each lot to get maximum value. So if you must sell and that is too much work, just take it all to the local used CD store (if there is still any nearby) and let them do the work and make you an offer.
In any case, identifying any rare or high value CDs up front will probably almost always pay off best.
