I have an old Free Spirit bumper mounted bicycle rack. It is several decades old but in good condition and holds two bikes. It was designed to mount on a steel or hardened bumper and has straps which then hook to the hinged edge of a trunk or hatch.
If you have a truck or trailer or older car with access to the top and bottom edges of the rear bumper, then this should work. To use it on a newer vehicle with a molded plastic bumper would likely take some modification. Asking $5, cash only please. See map for location and thanks for looking.