I second the ClearBlue Fertility Monitor. It was really key in conceiving quickly for us. We used this in conjunction with ovusoft software (ovusoft.com). It isn't free, but it wasn't incredibly expensive - maybe $25 or $30? Between the 2 tools we were able to conceive very quickly. I strongly urge you to use both - while I think both were great, I would have been a little lost without the other. Good luck!