Good luck with your search. The main problem will be shipping is likely to cost about the same as a case with a uke in it. Maybe look for a beater uke in a hard case and resell the uke locally. Also check Amazon and eBay for case with free shipping
I would recommend looking on amazon. Look at the new listings for hard cases and sometimes they have additional listings for used. I have picked up some hard cases for 50-70 bucks (I prefer ABS cases). Most of the time it's a new case that was returned.
Here is an example of how they also list used cases.
I play one of those Martins.. Be very careful you have a fourteen fret to the body tenor it is 2” longer than many tenor cases you will need length measurements of the case before buying a mistake. You may be best off with a Uke crazy hard foam and canvas case as several tenor cases are just not quite long enough Or very very snug and not a good fit. As many suggested shipping will be expensive so you need to look locally.. you really are not allowing shipping at your price even the cheapies like Glarry just won’t quite fit what you have.