I have been searching for a cheap mechanical timer to deploy a 'chute from a water rocket. I haven't gone out with the sole intent of finding one, but have made several stops while running other errands. Toys-R-Us had a nice selection from Z Wind Ups. These are really cute. Too cute, and too expensive, for me me to want to rip apart. I then found a cheap bath toy at Big K. It was easy to disassemble but, after playing around with it, found it was way too fast to serve as a deployment timer. So, the search continues.
At least I got my order of Estes motors from Hobbylinc in a timely manner (as usual).