In reality I only have roughly $800 or so invested in equipment for all my set ups. Bought basicly all new/used equipment save for my VHO set ups.
I got my 100g from my nieghbor for free. ( had a leak and I resiliconed it). Got 4 for free ( 2 20longs and a 29g )from a guy who went out of bisuness localy. Nobody would buy them because he never cleaned them up. Paid retail for my 38g long though.
Made all my canopies and stands.
4things you can do to save your self money BIG TIME.
1: TAKE YOUR TIME AND SHOP AROUND!!!!!!!
Dont be in a rush. Take your time even if you see somthing on sale that is just under retail and about to end. 90 percent of the time you will find the same thing on line or a day ot two later for much less. Anticepate exactly what you want and buy your pieces in NO particular order.
Since your filling the tank AFTER you buy every thing you dont need to buy anything ahead of anything else. If you take your time and shop around you will save your self BIG BUCKS.
2: KNOW YOUR EQUIPMENT!!! If your going to buy used Know what replacement parts cost,and how much the piece is realy worth,and what cuases what ever symptom the buyer is describing. I got 3 175w MH Ham. Tech. Mag. balasts less than a year old for $107 shipped at auction because the seller said they were on there way out and didnt want to pay for replacement parts. The bulbs would fire up and flicker out after 20sec or so.
Hamilton told him the ignitors where bad. WRONG. In most cases it is the bulb when they act like that with a mag. balast.
My wet dry system ( pro-clear 150 pro with skimmer and pumps) cost me $75 shipped. It had a crack in the body of the sump area. a little weld on #12 and a patch piece and all is like new. $250 unit for $75.
If you know what your looking at when you buy used,you can save your self BIG BUCKS. (DO YOUR RESEARCH BEFORE YOU BUY).
3: DONT WASTE YOUR MONEY ON BUYING ALL PREMIUM LIVE ROCK OR LIVE SAND. HAVE PATIENCE ( spelliing?)
You can make the bulk of you rlive rock consist of dry base or wet base rock. Which will cost you aproximately $5 - $8 per pound LESS. THATS ALOT!!

All you need is patience. Buy a few pounds of nice coraline encrusted rock after you have had you dry or wet base rock in place for a week or two. With patience in a month or less that dead rock will become live rock from what you have just placed on top of it. With the addition of some cheap and easy tp use addetives (
b-ionic,Purple up,Kalwasser)
the same baron looking live rock will become coralione encrusted beautifull rock, SAVING YOU BIG BUCKS.
4:
DO NOT WASTE YOUR MONEY ON LIVE SAND.
Live sand is for people who dont want to wait. That is fine for the 50 percent of us in the hobby who buy it so no offense ment to any one who uses it/sells it ( same goes for live rock)
Buy plane jane dry aragonite of your choice or dry sand of your choice.
The live rock will make the dead substrate live subtrate in a months time or less.
If that isnt enough for you thenvisit your local LFS and ask for a cup of the funky stuff from the nastiest looking substrate they have in thiertanks that is not covered in algae. 1 cup of that stuff will provide you with all you need to seed a large surface area of dead substrate.
Again THIS WILL SAVE YOU BIG BUCKS.
Remember, patience is the key to a healthy reef and a less costly reef too!