Here's a few quick pointers based on my own experiences:
You can get a Tom's Aquatic small CF lamp that's 13 watts and looks decent. It attaches to the side of the tank and comes in silver. The only place I have seen that sells them in the U.S. is this place:
It's about $27. Drawbacks are that it requires a special lamp (with a cover attached) so you have to buy replacements there and that it's only 13W.
A popular choice is the 9Wx2 (18W total) mini Aqualight from Coralife. It's 6700K and plant-ready, but does not come with any nice way to mount it. I have come up with a couple options but nothing I am real happy about.
I am also working on a high-tech LED option that's brighter than the Coralife 18W unit, and will end up costing about $40 - $50 in total. It uses a 10W 650 lumens single LED unit that gets so hot it must be attached to a CPU heat sink and fan. I'll post more info later on this.
As far as CO2, there are a couple options I have worked with that seem to work well for me:
1. If you think you will have more than one tank sometime in the future, it's best to invest in a 5lb. CO2 tank and regulator. It will last a really long time and is cheap to refill (at your local welding supply house). You can get the tank from them as well. I have two that cost me about $80 each from a Airgas, a welding supply place. The regulators come from eBay (new) and are about $65 as well.
2. You can also use a paintball CO2 canister with this one special regulator:
That product is much less than the Red Sea paintball canister option, but you will have to add a solonoid. I think I have seen them less, but this one is $50:
In either case, you will also need a diffusor. Fortunately these are not expensive if you get something other than the ADA models. Here's one that I personally like and use in several of my tanks:
That one is $15. Oh yeah, you'll need a bubble counter. They're cheap. If you want something cool, and have a 10 gallon or larger tank, get the spiral bubble counter, it looks really neat and does make bubble counting and setting the count easier:
It's $30 compared to ADA's version which is over $120 - wow!
I have not personally done the "biological co2 generation" thing, like the yeast mixes and such, primarily because the CO2 tank option is great and really gives you a lot of control and flexibility. I do use the ADA manifold splitters to get the output of one tank to into several needle valves for several tanks. One input with 4 outputs was something like $36.
Hope some of this info helps,