Additional to John's posting........embouchure on single reed instruments takes time to develop and the only thing that builds the muscles is practice....and that means practicing correctly. Sure, a lot of players were/are self taught and some greats were too and blah, blah, blah. take some advice and go take lessons if you're going to do this. There are a few things you can do to keep from biting through your lip, like folding a rolling paper in a pattern to act as a cushion on your lower teeth (found in almost all pros cases for emergencies, not just the occasional joint).
Proper technique in holding the instrument and covering the holes (different than pennywhistle/recorder) as well as breathing and embouchure can all be learned better and more quickly the right way and that means investing in some lessons.
I would also disagree on the type of clarinet that has been suggested. Some excellent student models are available in plastic and are very decent instruments. When you have developed the chops to play something better, you will probably also have a better ability to select something better. For instance, for many years one of the best was Buffet but you had to play ten to find one....maybe. The Selmer 10 was better but still not preferred by many. There are plenty of others but a high quality student clarinet from a good manufacturer will play easily and give you good service at a reasonable price.