I recently purchased a new one from the dealers for my resto project. I do actually have another brand new OEM one, unfortunately it has a dent on it (which I am confident a decent dent guy could remove) which occurred during transit, hence me buying another at the instance of the body shop carrying out the resto.
Aftermarket brand new ones can be had for as little as £130 but having looked at them, they did not seem to be that well made. Used are obviously available but even the best ones are 20 years old now and will no doubt have the dreaded tin worm to some degree.
Guess it all depends on how bothered you are.