All the time! I've lost count of the number of times I've had dreams where I'm at a carboot, or in a charity shop, or even sometimes in a current shop and there are rare variants the like of which have never been seen!
My favourite though, was one where I had taken a trip to a parallel universe and was in a retro shop that had an amazing range of rare variants, especially South American ones (including some unknown countries), however I didn't have long enough to really go through them as we had to get back and probably wouldn't be returning. I risked not making it home to buy some though, lol!