Yeast is a most magical friend of man.
You can easily culture yeast from some bottle conditioned beers made commercially. You will quickly learn how to make starters if you keep a yeast library on slants. I start my starters about 2 weeks out because when using a slant you are starting with a pinhead size cluster of cells.
First a 12oz starter then a 1/2 gallon starter. Pitch a half gallon to a 5 gallon batch and you will be rolling in a few hours.
I cook all my own bread as well, so I rely on them for food and drink.
Nothing like having a trillion of your dearest friends eating, fornicating and dying so you can have a loaf of bread or glass of beer.
/johnny