Topic: I am sort of new to this.

[AnswersinGeneSimmons]

OK, I posted an intro thread where those go so that is where I am at.

Anyway, I want to start a tank at home and I want to do better than I have done with the tank that I was pushed into running.  So I need to ask about setting up a new tank.  In case it matters, my price is USD $1,000 max but I would prefer to get started for around USD $500.

So let's say that I get  50 gallon tank.  Also, I want to have two filters so that I can alternate maintenance on them.  Would I need to get two filters that are both rated for 50+ gallons?  Or would I be fine with two 25~30 gallon filters?

[Cholly]

Kinda depends on what kind of fish you want to keep. Wally World has a fifty five gallon kit that has hood, light, filter, heater and even some starter food for just under $200 and a solid, basic put-it-together stand for just under $100. Very hard to beat. Filter is a hang-on-back type, not my personal preference, but nothing wrong with it. Craigslist is another possibility, but you have to be a little careful. For a first tank, I'd stick to new. Unless of course you find a deal you'd have to be an idiot to pass up, but those are few and far between, and you need a little experience to recognize them. What a kick in the head...
Personally, I'd go with two that are rated capable of 55-60 gallons. You want a minimum of 4-5 times water turnover per hour, I run between 8 and 12 times in my tanks. A lot will depend on the type, adult size and number of fish you want to keep. The general rule of thumb is one inch of fish per gallon of tank size. This only applies to slim bodied fish. If you like heavy bodied fish, throw that rule out the window.
I don't use charcoal except to remove medications, and you'll find pretty much nobody here replaces filter media until it's disintegrating. That's because that brown pudding-like substance that forms on it is the good nitrifying bacteria colonies that you want in your aquarium to keep it "cycled". Just gently rinse it in used tank temperature tank water if it gets so thick it doesn't let water through easily.
This is pretty basic info for freshwater tanks, saltwater is "a whole 'nuther kettle of fish".
Yes, I like bad jokes. I think punsters however, should be shot.

[Morgrid]

What kind of filter are you looking for? I assume you are talking about hang on the back style. Two filters is a good idea, although I have never done it with the hang on the back style. If you are getting a cannister filter I think one is plenty to run. Research the fish and plants you want first then get the tank, filter, decorations, and lighting to match them. With $500 you should be able to get setup nicely.

[AnswersinGeneSimmons]

Well, thanks for the info people.  No charcoal is an interesting idea.  Then I would not have to worry about it getting old.

Anyway, perhaps I should say what I have in mind.  Basically, a fresh water community tank and no fish that costs more that $10.  So when I am ready, I will probably just get a few tetras to get it started and then it will likely take me a half a year or so to get the tank fully stocked.

Alas, the wally world web site says that they don't have that kit anywhere within a hundred miles of me.  However, my local pet smart has a similar deal.  $209 for a 50 gallon acrylic tank with a clear back.  Oddly enough, they want $269 for the colored back tank.  I am guessing that my local art supply store will have a pack of poster board for $10 or so.

Next question would be what is the difference between the on back box filter vs. a cartridge that would mean that two of the former is as good as one of the latter?

[Cholly]

There are three basic functions for filters, mechanical, biological and chemical.
Mechanical removes particles, biological converts wastes into progressively less harmful materials, chemical removes harmful materials. Once the biological is functioning, chemical is not so necessary.
All filters perform the first two in some fashion. Chemical is the most expensive as you have to keep replenishing the chemicals.
Mechanical screens out 'floaties', stuff floating free in the water. The faster the current, the more it will suck up. Biological requires beneficial bacterial colonies to form, which will convert highly toxic ammonia, which comes from fish waste or any rotting organic(excess food, dead anything) into NitrIte, and another beneficial bacteria which will convert the NitrIte(still very toxic) into NitrAte(much less toxic than either of the first two). NitrAte we control with regular water changes, generally weekly, but frequency depends on the concentration of NitrAte. Some people like to keep their NitrAte below 20 ppm, some below 10 ppm. I'm kinda in the middle, as long as it's below 15, I'm happy.
Hang-on-back filters can let water bypass the actual filtration process if they get somewhat clogged. Canister filters force water through the filtration process, and don't allow any bypass. Undergravel filters use the gravel as both mechanical and biological filter media(yep, a third type, old school, but still used).
Of the three, undergravel is usually the cheapest initially. Chemical filtration is problematic with these, as powerheads are needed to make them really efficient, and they go where the chemical cartridges would using airlift. But the media never needs replacing, just regular vacuuming.
Hang on back are the next cheapest, media needs replacement occasionally, chemical filtration quite doable. But it can allow bypass if not maintained regularly. Most expensive for maintenance.
Canister are most expensive initially, but almost as cheap as undergravel in long term maintenance.
Sponge filters are another option, but they take up a fair amount of room in a tank. They're mostly used by breeders, kind of a speciality filter.
It all boils down to personal preference, really. What you are willing to spend(and when) and your maintenance preferences. I hope this was helpful and didn't just muddy things further.
If you have particular questions about undergravel, Essabee or myself are probably the two most likely to know the answers, we both have used them extensively(Essabee even developed one for planted tanks, awesome!)