You need one Main light, one fill light, one background light, and one hair/separation light. That means four lights minimum. The most-economical way to get four lights is to buy a pack-and-head system of 800 to 1200 watt-seconds, on average. It's REALLY important to have one light head that can be used bare-bulb, meaning without a reflector attached. To me, that is a critical accessory--a bare-bulb background light as an option. You need four backgrounds for studio work: white, black, old Master's Brown, and a swirled blue. Plus, some gels: blue, pink, yellow,red,purple. A very dark gray background is also very nice to have.
For light stands: two heavy-duty rolling stands for main and fill light; a boom stand for hair/separation light, and a short background light stand that will go very low, to up to about 48 inches tall. For studio portraiture, Speedotron and Photogenic Machine Company have the required types of lights and light heads to do classic studio work with the least hassle and at reasonable costs for lifetime-grade shooting. Having two, or three 16 to 20-inch parabolic 60 degree reflectors with mylar snap-on diffusers, barn doors, and a grid or two for each light would allow you to light entire groups in most any room or studio area.
It's easy to spend $5,000 on studio lighting gear. The only way to save much money on it is to buy the used,low-cost stuff available on e-Bay or Craigslist. NEW lighting gear costs a lot; used lighting gear is worth about 25%-50% of new price. AND it is a BUYER'S MARKET these days!!! ....make lowball offers!