Well, first of all, are you ready to be laughed at as you enter the pub, and be forced to hear a string of jokes that might possibly have been funny when you first heard them thirty years ago.Then you have to face being asked for Foggy Mountain Breakdown every night, and explaining that you haven't got enough strings.Then you have to face the hostile faces each side of you at the session, saying "Can you play that a bit quieter".Then you have to explain most nights that Duelling Banjos was in Deliverance, not Southern Comfort.
   Frankly, is it worth it? Probably only if you're some kind of thick-skinned loudmouth from Yorkshire, in which case go for it.
   Just get one that plays in tune at least to the fifth fret, if not all the way to the octave.Banjos are more flexible than guitars in this respect, you can shift the usidge up and down and re-angle it, which can help a lot. And seriously consider removing the plastic head it will come with, and replacing with some non-vegetarian skin. It will sound softer at first, but it will have more depth of tone and much more carrying power, with less tinny volume. Altogether better. You will have problems with it going soft in the winter, but there are ways of dealing with this.A bit of a rub works wonders.