Here is another camera slider that lets you capture linear and parabolic shots. The A&J Camera Slider has a foldable arm. It comes with an aluminum alloy rail and extends from 9.15″ to 27.7″ from end to end. You can use this with DSLR and mirrorless cameras up to 4.4lbs.
Costs under $120 at this time. More info is available here.