This is a peristaltic pump design adapted from emmett's Planetary Gear Bearing. It prints as a single piece, with captive rollers and no rotary wear surfaces. The only non-printed part is the tubing itself.
This is a proof-of-concept and can be driven (out of the box) with a standard nut driver bit. For real applications, you probably want to add a mounting feature for a small electric motor or similar. The pre-baked STL file is for typical 3/16 inch OD latex surgical tubing; for other tubing or to adjust other parameters, use the OpenSCAD file and customize as needed.

The prototype was printed on a Lulzbot TAZ printer. Depending on the printer you may need to adjust the 'tol' (tolerance) parameter, either to eliminate unwanted play between the gears or prevent them printing stuck together. Then just break it loose from the bed, thread the tubing through (latex surgical tubing works well) and Bob's your uncle.