I'm on Tricare prime
Have you enrolled in Tricare echo (if not, go to your tricare office and ask for the papers)? You'll probably have to. It's for duarble medical equipment, but totally free (if not it costs so little that I've never noticed). They cover walkers, wheelchairs, and most adaptive equipment. They cover up to $2000/month and if your equipment costs more than $2000 than they'll spread it out over several months. Like if the wheelchair was $5000 and if you ordered it today they'd put $2000 on April, $2000 on May, and $1000 on June. They say that you have to pay $30 for either every month you use it or for every piece of equipment (I don't remember which it's supposed to be), but we've used them for almost $10,000 on 4 pieces of equipment and haven't seen a bill for a cent (and we received our first piece of equipment last October).