I used to own the 8 gallon Biocube and really enjoyed it. Current USA's Aquapod and JBJ's
nanocube are other brands of essentially the same tank, so if you find a better deal on another brand that would be ok too. What are you looking to do with this tank? Even in the 29 gallon you are still somewhat limited on stocking (no tangs, angels, wrasses, etc. for example), but you can still have a very nice looking setup with a Biocube. Do you want a reef? The lighting is included and is adequate for many soft corals and some easier
LPS. No
SPS or clams would be possible though, unless you choose a brand that offers an HQI model.
There are other things that you'll need besides live rock. You'll need some aragonite sand unless you want to run a
bare bottom tank. A
hydrometer (cheap, but inaccurate) or
refractometer (more expensive, but MUCH more accurate) to measure
specific gravity/
salinity is a must. An
RO/DI unit is not necessary, but helpful. Tap water is not recommended for marine systems, as it can lead to algae issues. You can buy
RO/DI water at your
LFS or from the machine at Walmart, etc., but that gets old pretty quick IME. You'll need a marine salt mix unless you are buying premixed
SW from your LFS (many sell it, but mixing your own is a lot cheaper). Also, many people use a
powerhead in cube tanks in addition to the stock pump.