When you get your prescription, ask the pharmacist if you can get the same over the counter for less than the prescription charge.
Put all your towels through a hot wash after one use for the time being, as well. Tumbledrying could also be a good choice.
If you have flannels, you could use those for drying your feet instead, which would reduce the actual volume of washing/drying.
It's likely your shoes are contaminated/harbouring it as well. I would bin trainers and thoroughly clean the insides of other footwear that could take it.
And then act like you're in the gym. Don't walk barefoot, wear something that can be cleaned easily like flip flops/sliders.
And check everybody else in the house, as there's a good chance you've given to or got it from them.
I caught it from an ex (never had it in my life until his manky feet showed up). What actually worked for me was using hibiscrub, but that stings like a bastard if you have any open, weeping bits or splits.
If it doesn't heal or you're immune suppressed, you can go back to the GP.