How can I deal with a troublesome plantar's wart?

I’ve had a huge plantar’s wart on the bottom of my big toe for many years now (and it has spread to the toe next door).

For the past three years I’ve been doing liquid nitrogen treatments at my dermatologist’s, but it won’t go away. My copay has gotten too expensive so I’m not going to keep going.

Are there over-the-counter products or home remedies I can try? I’ve heard that genital wart cream can help, and I’ve also heard of a duct tape technique.

My friend had to have surgery to remove hers, and that’s a last resort.

Thanks!