Another thing you are going to have to consider is what type of light you want to buy, there are quite a few different kinds, like LED plant lights, incandescents, fluorescents, and compact fluorescents. All of these have different advantages and disadvantages to them. Here is a quick breakdown of the pros and cons for each one.
LED Lights: These lights are going to be your best option, but they cost a little more to do your initial set up, but in the long run they are the best cost effective since they last close to 60,000 hours and use just pennies a day to operate, unlike the other types of lighting. You can also get LED bulbs that produce the full spectrum of light so you will not need to switch out bulbs for the different grow cycles. Heat is also not a factor with LED grow lights since they give off almost no heat at all, so you do not need a ventilation system, or have to adjust the lighting to ensure your plants do not get burned.
Incandescents: Although these are cheap to set up and you can just screw these into normal light sockets, these are not the best lighting especially for tropical plants. These lights only give off 10% light while the other 90% is just heat which can burn your plants and you will need to have a way to vent the excess heat. if you are looking to just supplement a little light for your vine like plants that normally sit on your window sill then these are alright, but if you use this type of light it will cost about twice as much to run as a normal household 100 watt light bulb.
Fluorescents: These are good for vegetables and tropical plants, but you will have to change the bulbs for the different grow cycles. These are also fairly cheap to operate, they use 75% less power than the incandescents, but they do give off some heat, so if you do not want to burn your plants, you will want to make sure you adjust the lights higher as your plants grow. These lights will give your plants all the right lighting that they need to flourish in an indoor environment without too much hassle, just make sure you have the correct light spectrum for the grow cycle your plants are in and use them in a well ventilated area.
No matter which type of lighting you choose to go with, it is very important to make sure you buy lights that have the full spectrum of light that your plants are going to need. You are looking to replace all the different types of light and nutrients that the real sun gives to plants, so be sure you get the right ones.