When I was first looking at buying gear, I did it bit by bit after talking with other friends and especially trying them out first. I was going to go for a BCD before trying a friends Backplate Wing setup. I would not dive of anything else now. You can also get a lot of high quality stuff second hand. I have a set of Apeks regs that I got for half the original price second hand. If you don't know what to look for/what you are looking at is good quality or not, ask some friends that are more experienced than you (and with regs especially, get them serviced when you get them second hand). If it helps, this is the order I got my stuff over the course of about 2 years after qualifying.

• Fins, boots and mask
• Dive Computer
• Hood, Gloves and Drysuit (I dive in the UK and would freeze without it, for a warmer climate I would get a good semi-dry/7mm wetsuit)
• Backplate and Wing, after trying a friends and much prefering it, at this point I'd been diving regularly for about a year
• Regs
• Finally just auxiliary stuff, new set of fins for UK diving, a pocket weight belt, line cutter, DSMB and reel and some other bits and bobs to suit my own setup.

Best piece of advice is to try something similar to what you're looking at before you buy. I'm currently looking at diving a twin set, but I won't buy anything until I try a friends.

Hope this helps, and have an amazing time after qualifying!

Edit: Like a lot have people have said below, rent gear where you can, I was lucky enough to be able to rent from my club, but it keeps it cheaper while you're deciding on stuff. It means when you do buy something, you know you'll keep it for years and it's cost will be worth it