Look into using the Basal Body Temperature Method. It was able to show me that I ovulate 18-21 days into my 28/29 day cycle - and it didn't cost anything but a themometer. I learned the method through the book "Taking Charge of Your Fertility). The method has 3 basic parts to it.
1. Take your temperature when you wake in the morning (there is a temp bump of .4 or so degrees day after ovulation). That is how you know you have ovulated that month.
2. Check your cervical fluid - when you are your most fertile it looks and "acts" different from other discharge. That is how you know when to "Do It" in order to concieve.
3. (this is kind of optional, but helpful if you have a hard time figuruing out your fluid) Check the heigh, firmness, and openess of your cervix. It is High, soft, and open when you are your most fertlie.
Here is the web site that accompanies the book http://www.tcoyf.com/
I simply got the book from my library. It isn't really a hard method to understand. And it helped me get pregnant within 3 mo. (8 months for the second kid, but I didn't properly begin charting again until 6 mo of trying).
State Certified Early Childhood Special Education Teacher
New Mom as of March 2009!