truthfully, going the other way around is a lot more realistic.... there are way more coverless copies than covers out there...most folks that have covers, know they can find a coverless copy much easier than replacing the cover, and so they don't sell... if they do sell, expect to pay a big premium, since we are currently in such a cover centric driven phase of the hobby right now...
my guess is $300-500 for a front cover tos (depending on condition), and a little more for front and back cover... maybe $200-400 for the Jla cover
probably easier to find a copy that is incomplete but with covers, and marry with the coverless copy.... but even then, the sum of the parts is greater than the value of the whole...unless you are just buying to collect, then value shouldn't really matter... if buying to resell, probably a losing proposition...
I would sell the coverless copies (maybe to someone that has covers and will pay a bit more) and only buy complete copies....
thanks for answering!