Wind farms, as with solar farms and nuclear energy, have large up-front fixed costs and negligible marginal production costs. If the wind-farm produced _only_ 1 hours worth of energy, then $3.00 per watt would be spot on, as I understand it.
Likely the wind-farm will operate a number of years. Let's suppose it produces at 10% capacity for 20 years. That would be equivalent to 100% capacity for 2 years, which would be 50 MW/h * 24 hour/days * 365 days/year * 2 years = 876,000 MW/h
So now you have $50 Mill/ 876,000 = $57.08 per MW/h, or $5.7088*10^-5 cents per watt/hour.
Now, suppose the capacity is larger or the time lasts longer. The cents continue to fall per watt/hour