Simple Lock Box Puzzle

This little lockbox is technically not a puzzle, but I'm designed it so that I could later add a locking mechanism to a puzzle. I'm planning on later creating different types of locks, like a lever lock. I'm a little bit hesitant to try and design a tumbler lock because you need compression springs for those, and I want to make models that are fully 3D printable, so if anyone knows how to make a functioning compression spring, or a different way to make a tumbler lock without them, please let me know.

As always, any tips are greatly appreciated, and I would love to see Ideas on what I should make next.
(I focus mainly on making puzzles, but I can also make other Items)