A quarter dispenser I designed because I couldn't find one that I liked. I used Tinkercad to create it. Holds about $10.50 USD in quarters. The quarter body prints upside down with supports. (I have my support settings as "touching build plate")
The spring top and spring are placed inside the quarter body first, then the bottom is attached with super glue. I made the walls 2.3mm thick because in a previous design, the thinner walls allowed the layers to separate after about a week of constant pressure from the spring and the quarters inside.

Print settings I used:
-Print speed: 60mm/s
-Infill: 100% (concentric)
-Layer Height: 0.2mm (0.16mm works well too)
-Wall Thickness: 0.8mm
-Supports: everywhere

Spring Used: 18.26mm x 88.90mm x 1.05mm (23/32" x 3-1/2" x 0.041")