- An incandescent strip light - You can use either a full hood like the All Glass Economy Glass Hood (these usually only come in a 10 gallon size) or just the strip light, like this Perfecto Incandescent Strip Light. The benefits of the strip light are that it can be moved and used on any size tank, but it is harder to find in local pet stores and you need to either suspend it (not recommended) or put it on a glass top. It usually costs about $20.
- 2 Full Spectrum Compact Fluorescent Bulbs - You want the screw in variety, not the ones with pins at the base. They also must not be larger in diameter than the light strip they will be used in. Usually, a 25W bulb is about the largest that will fit, unless you can find the non-spiral U-tube variety: then length and the maximum wattage of the strip is the limiting factor (most are 2 x 25W max). These bulbs are quite hard to find in a full spectrum color temperature. Wal-Mart stores often carry a "Lights of America" brand that offers them in Daylight 5500K. Alternatively, many online light bulb sellers, such as 1000bulbs.com or SpecialtyLights.com offer them in spectrums that will work.
If you are looking for the cheapest lighting option with the highest light output, you should consider a CF Spiral bulb unit. Be aware that it is not the most efficent option, many systems are available that offer highly polished and engineered reflectors that give you the same results with a lower wattage because more light is actually getting into the tank. However, these will definitely cost you more up-front.
Pros: Best "bang for your buck" for smaller aquariums, easy to replace bulbs
Cons: Uses more power, creates more heat, less light actually gets into the tank
Total cost: $48: $20 for Incandescent Stip Light, $8 per bulb, $20 for glass hood/canopy