Fluorescent lights can be hung from the ceiling in an unfinished basement or a heated garage, but a light shelf provides more growing space. Several types are commercially available, but building your own can save a considerable amount of money.
The cheapest shelves can be built out of PVC pipes (see how here and here). The downside, however, is that the PVC frame may eventually bend, especially if you plan to put any heavy pots on it. A more durable option is to purchase wire shelves, on which it is easy to hang lights from the shelf above. Commercial-grade versions of these shelves are apparently available from Costco or other warehouse-type stores for a reasonable price, and they are very sturdy. Custom shelves could also be built of wood, if you are the handy type.
Four-foot fluorescent bulbs are the most inexpensive and readily available, so any shelf used for growing should be four feet wide. Many of the shelves available at cheaper stores (like IKEA) are only three feet wide. Shelves 12 inches deep and 48 inches wide will accommodate two standard nursery flats; shelves 24 inches deep can accommodate four.
Simple shop light fixtures are the easiest way to hang the lights; they generally come with cords, switches and adjustable chains. Two, three, or possibly even four can be hung across each shelf, depending on their width, allowing for four to eight bulbs. Some people who have built these shelves claim they can find the fixtures for under $10 each; I haven't been able to find any for less than $30, so look around.
The best type of fluorescent bulbs to buy for your light fixtures are T8s. They use less space, emit more light per watt, and have a longer life than the older T12s, and while they can be slightly more expensive, they are still much cheaper and more easily available than the even more efficient T5s.
For starting seedlings, cool white (5000K) or daylight (6500K) bulbs are probably best, as they encourage vegetative growth. For anything else, you might want to add one warm white or "gro" bulb per shelf. This will provide light from the red end of the spectrum that is missing from the other bulbs, but will be much less expensive than using the specialized growing lights in all the fixtures.