About a million dollars for the best, particularly if it has celebrity provenance. Kirk Hammet paid US$2 million for Peter Green/Gary Moore's 59 sunburst LP. They've started to acquire nicknames now, like stradivarius violins which just adds to the mythical associations.
Peter Green/Gary Moore LP = "Greeny" FKA "Collectors Choice No. 1" or "Magic"
Jimmy Page's LP = "Number Two"
Jimmy Page/Joe Walsh's LP = "Number One"
Billy Gibbon's LP = "Pearly Gates"
George Harrison/Eric Clapton's LP = "Lucy"
Eric Clapton = "Beano Burst"
Steve Lukather = "Rosanna Burst"
etc.
Of course this helps Gibson immensely because they can, like Fender, release limited edition replicas or reissues of legendary models at significant margin over the production line versions with minimal extra production costs. Funnily enough, it's estimated that over a thousand 59 Les Paul sunburst flame tops are left out of a total production volume of about 643 (according to burstserial.com). Mainly because in the late 60's it wasn't unknown for some players started to get 58 goldtops stripped and recapped with a quilted top. Or sometimes just refinished with a sunburst. Ed Roman was infamous for doing this and then flogging the modded instruments as original sunbursts with a refinish.