Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:2404631.

Many fidget spinners use bearings for weights, but even cheap bearings cost 50 cents. I know many of us started designing around Nuts but there are still many design that use bearings. I made a container that holds 3 pennies and fits into the bearing slots. Now you can spend a little plastic + 3 cents and the weight is very close.

These are designed for PLA shrinkage. Other materials may shrink more or less causing them to be too tight or too loose.