This is an excellent opinion, and there is definately some merrit to it, BUT...beviking said:The standard 55gal tank is 4' long. 2 2bulb shoplights (4 40Wbulbs) over a standard 55gal tank will give you enough light to grow lotsa' plants. Exactly how you get them to fit and make them look nice is the trick. At <$10 each (US), I think it's worth it. 4 bulbs@~$10 each=$40. $40+$10+$10=<$100
1)As Bviking stated, these cheap setups are very bulky and awkward looking, and really difficult (for the most part) to get them to look good. A planted tank is normally used to look peaceful, serene, and natural. Clunky, mechanical, "crap" on top of the tank really takes away from the look of the whole tank.
2)I have looked many times in the past at places like Lowes and Home Depot for strip lights to use on aquariums. I haven't personally seen any at less than about $18 each. These had the extra wide "flanges" used to reflect light from the bulbs. These are probably something like 8 inches or more wide, which means you cannot fit two of these over a 55 gallon tank (without major overlap). The double light fixture I have bought before was a 24" with no reflector at all for about $25 each (roughly). These served their purpose over a 20 gallon tank (with other lights added), but weren't nearly as satisfying as what I now use (explain later).
3)Bulbs for planted tanks (4' length) at my hardware stores (HD and Lowes,etc) are about $5 or $6 each, with only the most expensive being upwards of $10.
4)Another thing this answer didn't take into consideration was the cost of the wiring (not included in cheap strip lights), mounting hardware (except two or three screws (some don't even include this), and any additional features which make helpful additions to aquarium lighting (vent plugs, mounting brackets, water-resistant endcaps, etc.)
My Suggestion:
AH Supply Compact Flourescent Kits. You can get a 4 x 55w Kit (210watts) for $125 dollars plus shipping. I used this lighting on a 55 gallon before and had it suspended in a simple hanging wooden light fixture box 12" above the water surface. It was easy to move around, and put out enormous amounts of light. These fixtures can be viewed at www.ahsupply.com , so I won't go into detailing them. Basically they have the best reflectors around (increased light output), come with all the hardware, brackets, and extra stuff you won't even decide to use. They are also at great prices vs other CF strip lights. The only drawbacks are that you have to get something to mount them in. You can use a simple wood box, which is cheap and works fine (looks better than cheapo strip lights). After you buy the bulbs you like (just over $20 each (last longer than normal flourescent bulbs), build a simple hood, and buy the fixtures, I'd say you've spent $250 (including shipping). This should cover everything, including the spraypaint to color it to your liking. You will then have some of the most intense, non-bulky, efficient lighting you can buy, and you can upgrade your tank size without changing fixtures. Just for info, you can also go with just the 2 x 55 watt combo for $65 plus shipping. This will save you $60 dollars off my quoted prices and give you 2 wpg over your tank! Your choice.
