The trouble with a question like this is the price I'd be willing to pay is entirely based on security, capability, and functionality. I dont believe any currently on the market offer things remarkably different to warrant a price above and beyond the ~$50 to $100 for a lower end Trezor or Ledger. I imagine in the future features and security may improve to the point I'd pay more, but even then the answer is dependent on the value of the assets being protected.
The trade-off in that case is generally feature-richness vs security.
So while your true cold storage wallet shouldn't be instantiated in hardware that has a ton of additional functionality, it really would be nice for modern smartphones to have properly secured and isolated wallet functionality, just for the ability to safely spend day-to-day (though really, good lightning integration would be much better in that regard).