Depends on how many plants you want to grow.
One shoplight with cool white bulbs is about all you need to veg a few plants. You can add gro lux bulbs if you want to spend the extra money or add another shop light, shop light I'm talking about 2 bulbs, 40 watt or 32 watt.
Then for flower depending on how many plants you are growing. I usually recommend a 400 HPS or bigger but if you are only going to do 1 or 2 plants you can get and HPS light for $42. a 250 for around $100 and a 400 for around $115, if you have the extra money you can get an electronic ballast setup fro around $150.
Then you have to add pots or $2 trash cans from walmart plus dirt. Veg and flower nutes for around $30.
You can have a decent setup for around $100 - $200 if you are doing soil.
A great setup to start is a shoplight to veg and a 400 watt HPS to flower, that's what I recommend.