I have an Alien Bee which is fairly cheap but still of decent quality
Paul C. Buff - AlienBees
You might take a look at them. One of the nicest things about them is that they're light weight. I don't know of anything that I could recommend any cheaper. You could get by with one and a large reflector, but two make it easier... and three are nicer still. DON'T get hot lights, and don't get the real cheap "studio strobes" that sell new for $100 each. Garbage! You want something that has adjustable light output and adjustable modeling lights built in.
I normally use a Calumet/Bowens set of TravelLites (3) with umbrellas and a soft box. The soft box is nice, but you can get by just fine with the umbrellas alone. They're a step up from the Alien Bees, but you might find some on eBay for the same price. Alien Bees seem to hold their value pretty well, simply because photographers have heard so much about them. (Cheap but good quality) TravelLites are MUCH better in all aspects except their weight.
If you aren't familiar with lighting setups, I strongly suggest that you do some studying. You'll want to place the lights in different positions to create different moods, etc. It's not rocket science, but if you're going to get some studio strobes, learn how to use them to your advantage.
You can get by without radio slaves, but when you can afford them, they make it much easier, and you're less apt to knock one over when someone trips over the p.c. cord.
Hope that helps....