Have you read the grow bible yet? It’s totally free and might answer many questions to get you started. The type of lights you choose might depend on a few things, some can create quite a lot of heat. Fluorescent are readily available and you can make your own light system relatively easily and in most cases for not a lot of money. HID light systems have become very affordable and you can get pretty powerful systems for around $100 USD on e-bay. LED lights are still kinda expensive to start off with but give you the most Lumens/PAR per watt and will help keep the heat and the power bill low.
Here is a chart that can give you an idea of the various lights available and the electric use associated with each one:
You don’t have to go with any of the brands in the picture, it just gives some of the better known name brands as an example and there are other brands that will do just as good for much cheaper pricies to start off with. just do some research and shopping around and you can find some really good deals.
As far as how many seeds you should start off with, it depends on a few things. Are the seeds feminized? If not you have almost a 50/50 chance of the seed becoming male or female, you only want the female plants unless you want to make more seeds and seeded female plants are not as good as seedless in potency and seedless just makes better smoke or what have you. So if you have seeds of unknown origin, they are likely not feminized and the 50/50 rule will be applicable and so maybe more seeds is better as you may have to remove or kill off half your plants shortly after having them flower and identifying which ones are male or female. There are plenty of ways to take clones and so you don’t really need seeds to continue your garden from harvest to harvest.