Well first of all, Did you see the puppy yet? Well take that size of the dog. Then go buy the crate for her/him. No the puppies don't bite the crate unless you put your hands there or in the crate. I would probaly buy a small one or medium maybe sizes don't actually matter, The dog matters how big it gets and what breed it is.
The key to getting a crate is not to get it too big. You want just enough room for the dog to stand and be able to turn around to get comfortable, but not enough so that he can start using one side as a bathroom and the other to sleep.
Considering youre getting a young pup, depending on the breed, you have to figure in how big the dog will get. Unless you get one now, and won't use it when he/she grows up. Then get it according to the average size the pup will be when he/she is of the age where you won't use it anymore.
There are also instructions, by weight I believe, on each crate, as was posted above. As far as type, there are all kinds, and none is any 'better' than the other, per se. It's preference. I got the plain black coated wire one for my Schipperke and he was fine with it. I just but a lightweight blanket over it at night and he loved it.
Best I can do for ya, but many others are porbably wiser on the subject :)