shakespear:
The diving class I am interested in requires:
Booties, fins, snorkel, and mask.
After certification what order do I need to buy the rest of my equpiment in?
In the best order for you. I assume from your question that you don't intend to run out and buy everything right off the bat and many will say (and I don't disagree despite my actions) that taking your time is the best bet. Here are some considerations, in no particular order.
Wetsuit: If you're a perfect of the rack sort of person you can choose to rent for a while. Remember that peeing in a rented suit is bad form and some folks a grossed out by using a rental suit. If you don't always get the SAME suit sorting out your bouyancy and trim may be a longer term trial and error process.
BC: Are you able to rent one you are comfortable in? Around here that will rule out weight integrated for the most part so be prepared to dive with it all on the belt or with some perhaps tucked (non-ditchable) in pockets if any. Clip on weights may give some flexibility too. Not having the same BC all the time may be the biggest handicap to mastering bouynacy. [edit]--> Others have made a very good point that the BC is the core with all of your attachment points. You will have clips, cutting tools and other acccesories and getting all of that onto a rental will be haphazzard at best.
Regulator/Octo/Gauge set: Good enough stuff can always be rented and fit is rarely an issue. This is an easy one to defer till the end. The other side of the argument is that this is your air delivery and you don't want to leave it to chance.
Cylinders: It's a logistics thing. If you can rent immediately prior to your dives as well as make a timely return it's almost transparent since you need to make one stop for fills anyway. There are positives to owning your own cylinder and the payback is decent for frequent divers. In some areas your rental options will be AL-80, AL-80 and AL-80
So there are some thoughts. As I've learned there is is almost always more than one way to view these decisions. Another deciding factor can be when you "fall in love" with one of the components and you're confident that you are buying what will serve you well.
Good Luck and walcome to diving.
Pete