Note: Hello. Ok. So I have caught this saltwater bug and have been trying to create a tank that can be both beautiful and cost efficient. My current tank is insufficient. I want to house fish, inverts, and corals
You poor SOB...
If you were going to start either a 50 or 55 gallon tank and you were on a very tight budget, how would you do it, and how much would you pay for the tanks w/ and w/out the metal stands? First, would you prefer a 50 or a 55 gallon tank and why? Would you utilize a drilled tank or a non-drilled tank? (I'm confused about the purpose of an overflow box and a sump although, I somewhat understand them). What lighting would you use assumng you were going to house inverts? What fish or other specimens would you purchase? What other equipment, and specifically what brands would you use?
If you're on a -very- tight budget, don't pick up the hobby.
Don't bother with overflow kits; get a drilled tank. Get a drilled tank. Get a drilled tank. Yes, it bears repetition, but only because it's such a non-choice. The advantages of a drilled tank -far- overwhelm those of external overflows.
A sump serves a number of purposes -- these include more surface area for air exchange, increased air exchange through water turbulance from the returns, increased water circulation, housing all your equipment, increasing total water volume, and the ability to use it as a fuge/frag tank. If you can fit it in, I strongly recommend a tank with a sump; if you don't have a sump, though, you don't need overflows. THey're a great advantage, though, so I recommend you get one. You can build a sump out of a cheap/free 20g, some glass panes, and some silicone.
Don't get PC lighting. Just don't. I recommend T5 HO fluoros with individual reflectors; pack as many tubes as you can under your hood. If you want to go 'inexpensive', you can build your own hood pretty easily and cheaply. But you're still probably going to spend an inordinate-seeming amount of money on lighting.
If you have a sand bed and a good amount of quality live rock, you can probably do without a skimmer for a while, but you'll likely want one, eventually. But if you stock gradually that's something that you can likely avoid having to buy for several months.
I -highly- recommend Koralia pumps for general in-tank circulation. They're cheap, work great, are highly energy efficient, and are gentle enough that they won't damage most things that might crawl on them or suck anything in and kill it.
You can make your own Calcium Carbonate to raise your dKh out of baking soda by baking it in an oven. I recommend a kalkwasser drip as your primary method of replacing evap/calcium supplementation. If you can get the Kalk cheap as Pickling Lime or whatever, this is an extremely inexpensive method, but it can be a real pain if you don't use a pH controller and
ATO device.
Speaking of controllers and ATO devices -- these are fantastic to save time and hassle and to do things like deliver kalk. The new
Apex is reasonably priced and fantastically capable, and made it possible -- in conjunction with fans controlled by the temperature and a program to progressively turn off lights -- for me to do without a chiller in the summer.
Most RO membranes above 75 GPD are something like 75% rejection instead of 95%; this means you run through more DI cartriges.
You can probably get the tank for free, possibly drilled already, if you just hang out on the seller's forum long enough. Same for the rest of the equipment, really -- cheap if not free.
Live rock is best acquired cheaply from another aquarist, possibly with additional pieces aquired from other sources for diversity. You can use dead sand with a few cups of quality live sand from another person's tank or a LFS -- not that crappy pre-bagged live-sand stuff, but live sand scooped out of a tank of it -- which cuts down on cost.
Corals and livestock -- wow, that's something ~impossible to budget for. Anywhere between $5 and $500 a frag, averaging about $15-40, seems common, and popular fish range from about $10-$retarded. If you stay away from the fad items -- the expensive designer zoas, acans, and chalices -- you can stock the tank moderately cheaply. That's something you're going to be doing pretty gradually anyway, and for the most part, it can be done as your budget permits.
Personally, as far as fish go, I recommend going for hardy indiscriminate planktivores like damsels, clownfish, wrasses, and angels. And, of course, gobies and blennies if you like 'em. Your tank's really too small for tangs, which are apparently often a major headache, so that's a good thing anyway.
What kind of corals you get is entirely up to your taste, but the vast range of common acroporas and montiporas are pretty easy to care for if you can meet their requirements. Same goes for acans, plate corals, zoas, polliciporas, and the other coral that looks similar to a pollicipora that I can't recall the name of at this moment. Favia and galaxia corals are usually pretty easy too, but have long sweeper tentacles which can cause problems with placement. Soft corals including Xenia and kenya trees often grow quickly and easil -- too quickly and easily.

You need to take measures to contain their spread. (The only moderately reliable way I've found to contain Xenia is with corals that'll sting the crap out of them, or putting them on a rock isolated by sand -- but you'll still have to pull out overgrowth.)
You're going to wind up doing stuff wrong, hating a certain piece of equipment or lighting, or want to make other modifications/add other devices, but that's part of the whole process of learning what works for you. Figure out the minimum amount of money you think you're going to spend, and increase it by 50%, or better yet, double it.
Buy (and use!) a QT tank. A cheap 10g with a light sufficient for fish, a heater, and a small powerhead for circulation pretty much has you set. Buy (and use!) anti-flatworm dips. And also, get a tablet of Interceptor and use that to dip any and all acros and things which were house with acros that come into your tank.

Most corals can go into the DT after a dip and a day or two's observation, but fish should have a full two to four weeks. There is -nothing- worse than having to chase an already sick fish all around the tank while breaking corals 'cause it didn't look like it had ich when you bought it.
Spend time looking at tank threads and reading books and websites, and copy people who have tanks you like.
