Free 

This is just a simple model. I printed 0.2mm layers heights. There are holes for 6 x 2mm round magnets. Flip on flat side before printing. 2 or 3 shell layers, 10% grid infill. This should be an easy print. I used black filament.
There are two cacti. Mirror the unsymmetrical cactus if you want three kinds.
Figure out copyright with Google if you print for profit.
Names are used only to indicate the source of a result. Polyzon is not affiliated with the listed sites.