I can't argue with the choice of an ADA tank. There are alternatives (though not for the misted glass versions that I know of) but they appear to be incredible looking tanks so if someone is going to splurge for ADA products (other than AquaSoil) then the tanks seem like the appropriate thing to pay the premium for.
The ADA soil additives always tend to cause an argument but the fact of the matter is that many people have great success with just ADA soil while skipping the powersand and the bacterial additives and other chemical/biological solutions.
When it comes to filters and in tank equipment the ADA price premium really rears its ugly head.
Cal Aqua, Gush, etc. all offer some alternatives when it comes to intake and return tubes and pre-filters that tend to be far less expensive.
Finnex has some good nano-tank equipment - a clip on light that provides a decent bit of light (and you could always order a second light) and a canister filter similar to the zoomed 501 that is less than $40 I think.
You probably ought to seriously consider the Finnex Pico 4G Glass Deluxe+ kit as it comes with the clip-on light, the canister filter and a pretty nice 4 gallon rimless tank with rounded FRONT corners. The whole package runs $75.
Personally I would focus on the actual tank, the canister filter and getting a 'real' CO2 system as my priorities in terms of budgeting expenses for the tank.
CO2 is going to help the plants a lot more than getting the full ADA substrate system would (if you have to choose between the two).
In terms of CO2 look for either a full CO2 set-up (with a regulator) or a paintball set-up (which can be found around here for ~$50) because the ones with cartridges will break the bank in terms of regularly replacing them.
I would take Justin (RootMedic) up on his offer of answering questions about the substrate systems. He is very helpful and is straightforward and helps make sure you get what you need rather than just pushing one of his products off on you.
If you can not afford the light that you really want you might consider just using a desklamp with a 6500K (or other daylight spectrum bulb) CF bulb put in it which you can find at Wal-Mart, Home Depot, etc. Then you can save up for the more expensive (better looking) light later on. A small tank like you are getting can easily be lit up with compact flourescent lights so the options are cheap and plentiful.