You can grow with just about any light really... theres no hard and fast rule on what has to be used.
Common lighting types, are HID (High Intensity Discharge, such as HPS and CMH lights), Fluorescent, and LED. HIDs and LEDs are usually used to cover your entire grow, where Fluoros are usually used as supplemental lighting or for young plants that cant handle the light intensity of other options.
As far as wattage, that's not exactly the best measure of light. Really, you want something that will have a light coverage area that fits your grow space and can provide enough umol to your plants in the proper spectrum. Figuring out umol of a light thatisnt specifically noted is a pain in the ass though.. much easier to measure LUX using a cheap lux meter or phone app.
LUX is a measure of light intensity at an exact point. As the plant matures, it can handle an increasing amount of light intensity. Seedlings prefer less light, in the 5-8k LUX range. A vegging plant prefers 15-50k LUX, and a flowering plant can handle up to 75k LUX. As an example, a t5 fluorescent light puts off 8-10k lux at a distance of 6in.
And as far as your electric bill... that's simple math. Just check your electric bill for the price your electric company charges per kilowatt hour.
The US average kwh costs 13.31 cents. So put into practical use, let's say you have a 1000w HPS lamp running by itself with nothing else. Well assume you have it on an 18/6 schedule for 30 days, then a 12/12 schedule for an additional 75 days.
1000w = 1 kwh = 13.31 cents
1kwh x 18hours x 30 days = $71.874
1kwh x 12hours x 75 days = $119.79
So across an entire grow, 1000 watts being used would cost on average 192$.. about 55$ per month. You can do that math using the wattage of your specific setup, to find out your running costs.. but on average, it's really not very much if you do a per plant breakdown of the cost of electric