I've been looking for cheap rental cars for a ~3-5 day trip in July-September (exact dates to be determined; I plan to use company vacation so I'm very flexible.)
Jackson seems to have the cheapest rental cars (Dollar/Thrifty for <$30/day, though reviews are very bad, and $50 otherwise.) West Yellowstone and Bozeman are both in the $60-70/day range excluding taxes & fees (likely $80-90/day after.) Dollar/Thrifty only allow returning to the same location, no exceptions. Enterprise has a presence in Jackson & Bozeman, but returning to a different location incurs an $80 drop fee.
Is there any easy way to get from Jackson to Bozeman without a car? Of course, I'd prefer not to have to return to Jackson after West Yellowstone, if ultimately leaving from Bozeman. If there's no easy solution at a reasonable price, I might just have to return from Jackson instead of Bozeman.