What other low cost options are there and do they work with cell phones so that they get dual usage and thus the costs are amortized over more devices?

The verizon 5g home looks pretty good [0] if your current options are only dsl or cable which they are for a bunch of americans. It's even got a 4g backup connection.

[0]: https://www.reddit.com/r/verizon/comments/9lqp6n/i_got_5g_ho...