For most digital work like this you can use most any non-polarized cap. With non-polarized caps in digital circuits your only real paramter beyond capacitance that you are worried about is the voltage rating. With a standard 5V digital circuit it is best to make sure your cap's voltage rating is at least 10V (some will say 6.3V.
Something like this; http://www.mouser.com/ProductDetail/TDK/FK28X7R1E104K/?qs=sGAEpiMZZMt3KoXD5rJ2N48tYEMqcp4xEeCIZV2cepk%3D $7.50 for 100 rated to 25V
All that said, if you already have 0.1uf polyester caps in your junk draw, then by all means use them but if purchasing them new, the polester caps are usually (from my main supplier mouser) slightly more expensive.
http://www.mouser.com/ProductDetail/Panasonic/ECQ-V1H104JL/?qs=sGAEpiMZZMv1cc3ydrPrF%252bfZ13WJ%2Fr1%2FEY9wPof57Ts%3D $7.80 for 100, rated to 50V