Hi It depends where you are and if it has 3 point hitch, working air con and that kinda stuff. round us in Manitoba/ Canada with none of the above, auction price would be $3000 or less for a rough one, to about 5- $6000 for a very nice one. The further south in the U.S you go they seem to get up to $8000 + guys seem to love them. There are dealers here wanting stupid prices but they sit a fair while until the discount to move it on kicks in. I know of an 1135 with 3pth with an $11.000 price tag right now. Its been there well over a year. Here guys don't really want 1105's too much they are under powered for the size 1135 is the same tractor and a turbo fitted so has a little more poke.
According to most of the MF guys on this board there are no problems with these 11 series tractors. I was told I was an idiot more than once when I commented on 1135 and 55 transmissions being junk, and having problems like the other poster said. Ive worked shop and wrecking yards to get wise to the problems Good luck in your search, and be careful with multi power if it's fitted (12 speed) and the pto clutch packs if it's worked hard for a living, The fine splines in the pto drive line can strip too either at the flywheel or inside the coupling from the gearbox to the rear axle If ones worn the other is not far behind usually. The outer of that shaft that takes the gearbox drive to the rear axle can also strip too in some cases with years of hard pulling.
They are one of those tractors if you get a good one they are good. if you get a bad one you get a hole pile of trouble just like anything else from my experience. you also have to remember they are 30 odd years old and not the most quietest, comfortable, convenient tractor drive, and to spend a long day in they have there operational quirks too . Regards Robert