after a number of years of trying to "make do", i went to my LBS and tried to buy a chainring wrench. the mechanic GAVE ME his. he said they were cheap... i don't doubt him. it's just a piece of 1/16", on a good day, stamped steel that's been bent in a couple of places. pretty flimsy, but usually works.
BTW, when i don't have the tool handy, i've managed from time to time to get them off, and on, by vigorously turning the male portion while imparting a lot of sideways torque. the friction heats up the female portion causing her (
) to bind in the spider.