K.M.
I used the Clear Blue Ovulation Monitor. I bought a used one from a friend of mine for $70 & that's what I use for my third daughter. They say not to buy them used but they say that about breast pumps too. I had success with both as being used. Just clean them well, I even found one on eBay that had been professional cleaned so they are out there too. It keeps tracj over a period of time of when you ovlate so then it can tell when is the best time to try.