I pour a little rubbing alcohol, the cheap stuff you buy for a dollar a bottle also called isopropenal, on my toe nails after I shower. It works well for me. The alcohol soakes into the nail and the fungus.
I had a severe fungal infection under my big toenail. My doctor prescribed antibiotics that I would need to take for a year (lamisil?); this drug had a risk of serious side effects and also required completely giving up drinking alcohol for a year! Before taking the antibiotic, I decided to try just applying rubbing alcohol (50% alcohol readily available and cheap at any pharmacy) twice a day.
I put the alcohol in an eye-dropper and was careful to get as much under the nail as possible; I also cleaned out dead skin if necessary. I did this twice a day, and also at any time when my feet got wet. I saw progress very soon, and the fungus was completely clear in 6 months. I did not lose the nail as had been predicted. I did not change my diet, stop drinking, or take any special supplements - just the external rubbing alcohol directly on/under the infected toenail.
Worth a try for a month; if you are diligent you will see progress and this has to be the cheapest, easiest way to handle the problem.