340 QUESTION??

Don't mean to be numb here, just trying to get some ideas about todays reality! The 340 has always been my favorite smallblock since owning two of them {'69 cuda + '69 swinger} back in the 70"s. Hope to have one again before pushing up daisies.
Just looking for a ballpark idea of what price is a fair price to pay for a good rebuildable long block 340, 69-71 era in stock form? How about one that is already rebuilt? Buyer beware right, with all the crooks out there! Thanks!