I use Glacier water as well. In fact I just got 25 gallons for 9 dollars! Can't beat that! I drink it as well as use it for my tank. I use it for my Birds water and my Cat's water. It's cheap.
If you want to go cheap on saltwater your going to have a BAD time. The only way you can really cut cost is in the rock and sand. You don't need to buy all of your rock "Live", you can buy a few pounds of it "live" and the rest just regular rock. The regular rock will be seeded by the "Live" rock you bought within a few months time. The Sand can be bought live or just regular normal sand. I got 30 pounds of normal sand for $15 dollars at petsmart, compared to 20 pounds of live sand for $40. Depending on how big your tank is, you can buy a small bag of live sand for much cheaper and a few pounds of normal sand. Just put the normal sand as your bottom layer and pour the live sand on top. Within a few months all of your sand will become live.
That is really the only way to cheap out. Depending on how deep you want your sand bed and how big your tank is, it will make it more expensive or cheaper. The same thing with the live rock. Its suggested to have 1 pound per gallon of live rock in your tank. So if you are starting a 29 gallon tank, buy about 5 pounds of live rock, and 24 pounds of normal rock. Live rock goes for $6.99 a pound normally.
When it comes to equipment, what you pay for is what you get! you need powerheads for water movement, filtration, heater, the tank, lighting, a GOOD Skimmer, sand, and rock. Go with the best stuff, because if you really want a cheap FOWLR
tank you will not want to be buying fish over and over because they are dying on you. Some fish can be very expensive. My most expensive fish right now in my tank cost me close to $70 dollars, and most marine fish come with no guarantee! You get it home and it dies, your out of luck and money!
So keep that in mind when starting up a FOWLR
tank! Also READ up on the cycle process! This will also save you BIG bucks in fish cost! We recommend not doing a fish in cycle because the fish LFS
suggest doing the cycle with will just end up causing you problems down the road if you choose to get something else. The Damsel fish is cheap and hardy and that's why they suggest them to cycle your tank, but they end up becoming little monster harassing everything you put into your tank after. Also it's just cruel to subject fish to that kind of treatment. It's like letting them swim in a toilet without the plumbing to flush! The fish end up getting burned gills and their life span can be shorten. So a fishless cycle is the way to go and it is not hard to do. There is two methods for a fishless cycle. You can read about them on this website! One is the shrimp method which is just throwing some uncooked shrimp into the tank and let nature take it's course for about 3 to 6 weeks. The other is the ammonia method which is adding ammonia to the tank in the right amount to build the bacteria that eats the ammonia. There is more to it, but each method adds ammonia to the tank so the bacteria can start to form in the tank to effectively eat the fish waste.
So as you can see, the best method of to go cheap on a FOWLR
tank is to do it right the first time. So you can enjoy the fish without too much worry of them dying on you. It also helps to learn the process of adding fish to your tank. The drip method of acclimating your new tank friends is the best method!
Learn from me! I wanted to go cheap on my freshwater set up. I ended up killing ALL my fish because I didn't cycle the tank, and I got the cheapest crap Wal-Mart could provide. I got out of doing tanks for a good while, before I started to learn about everything. I ended up going with a 29 gallon Saltwater as my next tank, and now I am about to upgrade to a 120 gallon long tank! :-p My only fish deaths now are due to jumping out of the darn tank, and not water quality. I fixed the jumping now, so no deaths to report anymore. Hope to keep it that way!!! Also don't get discouraged if some fish die because of jumping or an accident. It happens in this hobby, but after doing research and learning as much as I could, I have not had any more fish die on me.
Sorry for the long winded post. :-p