There is no ATM. Bring enough cash for your stay.
It's a very small town, everything is within walking distance.
Zumbahua's main square is host to a big market where you can buy anything from livestock to ponchos to TV remotes.
There are a few small hotels near the main square (~$6-8)
Lake Quilotoa: There are buses to the lake during the day ($1) or you can hire a camioneta for ~$2-3 depending on your bargaining skills. The lake is 12km from Zumbahua; hiking distance for those who feel so inclined.