Use a pair (or more) of these 3D printed risers with any length of 2x8" dimensional lumber to raise an object of the ground. This was designed to lift a large cat litter box off the ground so it would not impede air flow from a heat vent in the floor. 

Model printed on a Prusa i3 Mk3S with Warhorse Black PLA. Top and bottom layers were excluded to show the honeycomb infill. 

The 2x8" lumber is a very tight fit, you may need to sand your boards down in some instances. No need for screws or nails and the riser can easily be taken apart with some manual force or light blows with a hammer.