Depends... there are a lot of cars out there. Some good, some not.
Unfortunately, most mid 60's muscle cars (especially Mopars) are fetching crazy money.
Keep in mind that a lot of cars are being called classic's or muscle when in reality, they're just old cars. For instance, there are a lot of late 60's Chevelles that started out as 6 cyl clunkers, but now, they sport a bigger engine and maybe some flashy paint and they're being called muscle cars. Unless they have changed out transmissions, rearend, suspension pieces, they are what we call in the business (an old whore in a new dress).
I should also add that one should be mechanically inclined or very well off as nobody works on these cars cheaply.
A quick facebook search showed cars like this that are well within your price range. (with maybe a little left over).
1968 Chevelle 350 cid motor Turbo 350 trans Power steering Power front disc brakes Ice cold air conditioning Stereo 12 bolt rear end Painted in 12/24Interior is in great condition Car shows well and drives great. $39,500
