Mine are just commercially sourced blowers of the type used for inflating childrens bouncy castles. As you are in USA I would suggest:
A shop vac which will blow as well as suck. Probably no need to buy a new one though.
For a small set up maybe a hair drier.
I heard of one guy trying one of the hot air hand driers like you get in a public toilet.
Imagination is the thing. You will find something, probably free, if you work at it long enough. Stuff like the above is good for a bottom draft forge as all the heat is going away from it. Be more careful if you construct a side draft though as the tuyere will get hotter and might lead to damage to the blower so either use a water cooled tuyere or make sure there is a long pipe between that and the blower.
I regulate the speed on mine by connecting them through a dimmer switch. It is cheap, simple and it works.