I designed a small clip-on attachment for the cupholder in the center console to hold some quarters. If you have a 3D printer or have access to one feel free to print one off for your Prius! I can't post links because this is my first post, but you can go to Thingiverse and search for "Prius (Gen 3) Quarter Holder" If there is enough interest I may be able to print some and have them shipped out for a price.
$2? Where? Filament is still expensive, unfortunately. Neat idea. The price point would have to be competitive. +1 if...
I hope you printed it out of PETG or ABS. PLA will soften/deform in a hot car. I had a couple PLA prints in my car that didn't survive last summer.