Here are my thoughts on Scuba Equipment (for what its worth). This is the same advice I give all new students at our shop.
In no particular order ...
1. Buy Once; Buy Right. Your skills will improve drastically. Buy the gear that is going to suit you a year from now - not today! Buy high quality gear that is meant specifically for diving (not snorkeling). Consult Scuba Diving Magazine for reviews. Ask questions inside the equipment forums here on this site. Don't rush into a purchase -- make informed purchases. Don't buy equipment now and then realize you should have bought something different a year from now. A great example is the hoseless computer. In an effort to save $100-200 dollars, many new divers will get the computer with a hose attachment. After 25 dives, they regret that decision and buy a hoseless computer - now they have bought twice and paid almost twice as much.
2. Profile what your diving will look like. Take a serious look at how you will dive in the future and buy equipment appropriate for that type of diving. If you are flying off on an ongoing basis to the caribbean, then a light weight BC may be better suited than a tech rig. If you are doing Wreck diving, that may require different types of gear. Coldwater diving could mean an environmentally sealed regulator. What type of continuing education are you looking at and buy gear suitable for that level -- again planning a year or two in advance. Are you planning on taking a Nitrox Class (you should be)? Make sure your computer is Nitrox compatable (most are).
3. Don't buy inferior equipment. This would fly in the face of point number 1. You will get inferior results. It would hamper your diving experience. It would hamper your ability to advance as a diver. Wal Mart dive gear will get you to the bottom of a pool, but not much further. Now you are buying twice. I was certified almost 20 years ago, I still dive in the same mask -- if it works for you, why not.
4. Don't buy through catalogs or Internet. Dive gear is finicky. Buying it in person allows you to put it in your hand and try it on for size. Even a simple thing like a knife can screw up your equipment configuration. If you are not happy with a specific shop, look around. Remember, shops carry a specific line -- it's not the only line in town. Additionally, if you have a problem, it has been my experience that an LDS will be very helpful as where the Internet is very painful.
5. Buy all your equipment at once. You'll get better 'package pricing'. Also, don't feel like you can't negotiate. If you are buying more than one 'package' or paying in cash, you may be able to get a deeper discount. The great thing is most dive shops are small businesses and there is always some good ole fashioned bargaining with small businesses.
6. Suck it up. Diving is equipment intensive -- just like rock climbing, golf, skiing, etc. Having your own gear will hieghten your experience 10 fold. Once you bite the bullet and buy the gear, diving is very inexpensive. If you own your own tank and weights, local diving cost as little as a quick fill -- $4-8 dollars. When traveling, a two tank boat dive cost between 65 and 90 dollars. That ends up being around $20-30 dollars an hour. Sleeping on vacation could be more expensive than that. Please note, diving is very addictive -- while you may have what you need -- you may continue to accumulate equipment :05:
7. Try before you buy. Whether it be fins or a computer. Ask the dive shop if you can try the equipment out in the pool prior to writing the big check. You may not be able to try every piece, but probably there is enough demo gear around the shop.
8. Learn how to maintenance your equipment. Perhaps take an equipment specialist class. Go through every piece and intimately understand how to maximize the life out of each piece, how to clean it, how to store it and how to do simple fixes. Have extra parts available so you can do quick fixes at a dive site -- orings, mask straps, fin straps, etc.
9. Streamline your equipment. remember to buy your fasteners and clips (and safety equipment) while buying your equipment. Add to the discount. In fact, while negotiating you can ask the shop to "throw these items in for free". Doesn't hurt to ask.
10. Send in your warrantys (keep copies and send certified mail). Put together an equipment list / folder for receipts and service records. Purchase equipment insurance in case it is lost or stolen. Also, in the states, if a diver reaches a professional track during the year (such as Divemaster), much of this equipment MAY be tax deductable -- consult your own tax specialist on this. Doing this while you have no equipment and a new diver will make it much easier later on.
Hope this helps