the little bottle I got from the drugstore (Canada) was probably more like 3-4 dollars... it includes a little plastic-knobby stick, for 'painting' the Iodine on.
I was one of those whose yellow circle disappeared in under an hour, at first. After a few months of a blackstrap molasses, kelp and lemon drink, and a few other things, it was much better. So were my low thyroid symptoms. The stain would be still visible 12 hours later.