Simple Filament Mount for RepRap Prusa i3. Clips over the top rail of the acrylic frame. Easily slots together. Very sturdy and allows filament to roll easily under minimal pull from the extruder. Doesn't take additional space on your work table.
UPDATE: My most recent spool orders have come on larger diameter spools so I have made an adjustment and included a longer leg for this design that will accommodate a wider range of spool sizes.