A couple resources are helpful...
- If you are logged into ebay, you can do a search then choose "completed items" to see recent closes - this can be a very narrow set of data, and you have to eyeball for matches and confirm which items really closed
- If you want to see a broader set of data, see http://www.prepal.com - this isn't necessarily up to date, and may include "false matches"
Neither is definitive, but between the two you can get a flavor for whether you are in the ballpark...