there really isnt a solid answer to this question. a power compact fixture would do, but honestly long term they arnt "inexpensive" due to having to change their bulbs out more frequently for best results, they prob. will be the cheapest way to go off the start, but again the bulbs can add up over time. next would be t5s, which i personally like the best. they are alittle more money but run cooler and offer many different variations of looks depending on the K bulbs you choose. since they usually are 4, 6 or 8 bulbs you can mix and match making your lighting more how you want it. buying bulbs for these can cost alot after awhile but will last alittle longer then the compacts before needing to be replaced. then you have halides which can prob. be found for the same price as t5 setups, and some alittle more but long term with these you'll be paying it in electricity. bulbs can also be up there in price too. then you have LEDs which will empty your wallet to buy, but run the coolest, and are supposed to last the longest before replacement, not to mention saving on your electric bill.
in your situation i would start by searching your area for a local reefing club. you'll find all kinds of things there. i would then check ebay and craigslist but keep in mind this is a very expensive hobby. i personally would not skimp on lighting or a skimmer.