Printed with PLA at 20% infill — possibly more than necessary, but I wanted to be sure my mouse would be safe.
At a speed of 200 mm/s, the print took about 150 minutes and used around 30 grams of filament.

I used tree supports for this model and had no issues with them. Regular supports could also work, but they will use more filament (around 40 grams).

I've also added three holes for M3 screws.