Hey hey hey,
POAS addict in the thread
I used OPKs when I got pregnant, brought them in bulk from ebay and they have always been just as good as the pricey ones. I got 100 opks and 50 ics for £13 and I still have loads left to concieve the next bubs!
If you are already in a cycle, it's easier to work out when to use them. You want to start using them between 8-10 days after AF (I started of at 8 days as I tend to OV quite early and didn't want to miss it) but most people will OV at around the 10-12 day mark. Keep using them at the same time each day (probably best to use FMU for ease) and watch how they change.
For an OPK to be positive, the line needs to be as dark as or darker than the control line. Just a line in itself doesn't mean you are OV. The hormone should get stronger though, so if you track the OPKS over a week or so you will learn what is positive for you over time - some people never get it as dark but are still OV. As I am not, I just started taking them randomly and caught my OV today. Pricey at first, but worth it to help you work things out.
Personally, even if you don't intend to temp I would get to grips with
www.fertilityfriend.com - take the charting courses, a good way of killing time until TTC! Some people will find they need to also use temps and to check cervical mucus to get a complete picture of what is going on, for some, OPKS are enough. I didn't get CM before I got pregnant with Edan, but using OPKS and temps I can show you on my chart where I OV'd, and exactly where I implanted. OPKS will tell you what is going on around OV, but temps can give you a much better sign of what is going on over the 2ww.
Annnnnnd relax. HTH -x-