You can reuse brewing yeast. There are dozens of threads on this very topic here at HBT. You're looking for threads on yeast washing, yeast banking, reusing yeast, etc.
I run a yeastbank for my local brewclub - because of the way we re-use yeast, we rarely need to by commercial yeast (unless, of course, that strain isn't in the bank yet). Managed properly, brewing yeast can be re-used indefinitely. more conventional yeast-washing methods allow yeast to be reused 5-10 times before replacement.
And yes, you can reuse them in bread as well - just make sure you wash them well first, or you may get hoppy-tasting bread.
Now that I think about it, hoppy bread may not be a bad thing either...
Bryan