Many areas have rules that require the utility to offer "net-metering" where you pay for the difference between what you produce and what you use. When you have demand exceeding production you draw from the grid; when you have production exceeding demand you "sell" to the grid.
If you look at your electric bill it will tell you how many kWHr you use. Lets say you use 720 kWHr in a month, or an average power of 1 kW. But wind power generally produces on the order of 25% of the rated power of the machine because of variation of available wind.
So you would need a 4 kW generator to produce and average of 1 kWHr.
If that 720 kWHr costs you $1000 per year, you might break even if you could get a 4 kW rated generator installed for $10,000 and you could depreciate it, maintain it, and pay the interest for 10% of the cost.
I think you would have a hard time achieving those numbers.
The government (that is all of us, via our taxes) pays 1.5 cents per kWHr subsidy to companies that produce wind power. That is why you see so many wind-farms in places that have wind.