Generators can run you anywhere from a few hundred to a few thousand. You can get a decent one from <a target=_blank class=ftalternatingbarlinklarge href="http://www.costco.com/Common/Search.aspx?whse=BC&topnav=&search=generator&N=0&Ntt=generator&cm_re=1_en-_-Top_Left_Nav-_-Top_search&lang=en-US">Costco</a>.
To determine your requirement, you need to add up all of the items that will run at the same time - refrigerator, vest, nebs, etc. This is the max amount. Since you will know when you are running on the generator, you can control what is running (except for the fridge, that's going to kick in whenever it needs it. ) The genny will have a maximum run time, usually only a few hours, then you would have to refill it with gas (unless you get a bottled gas/propane variety, which is higher cost.) Refilling the gas tank on a hot generator is not a good idea, so it would have to cool down before you refill it. You will also have a noise issue (if you don't live out in the woods.) And if you are in an apartment complex, you may not be permitted to have one. The huge ones would run your whole house, but what you probably need is a small one that you can plug individual components into as you need them.
Another alternative, if you have the room and no restrictions, is solar. Go Green! Forget wind power - unless you live where the wind blows at least 15 miles per hour ever minute of every day and never blows over 40 mph!
Personnaly, I think having a generator is good idea.