Toe Heater at your Desk

I hate dress socks.  My problem is my feet get cold in the winter time, all the time.  I sometimes wear my supper thick snow socks on less formal days but for the most part I'm stuck with thin dressy black socks and un-insulated dress shoes.  It would be great if there were a little heater just like the one in my car that would blow hot air (not like those electric ones that always trip the breaker) and I could keep my toes warm on those snowy days.