I recommend looking for ovulation tests/pregnancy tests on sites like ebay — the test strips you get there are *just* as good over-the-counter (and sometimes, they’re easier to read too). I could usually buy a pack of 50 for around $6 – $7 on there, including S&H.
If you had irregular periods before you were on birth control, I think it would be a great idea to start using OPKs and consider taking temperatures too (the suggestion of using Fertility Friend is excellent — I think a 3-month membership for all of the perks and all is about $15. I don’t remember anymore how many services you could use on a free membership. I was there for a LONG time).
Generally — that is, if you did have a regular 26 or 27 day cycle — you can start testing with OPKs around calendar day 9. My ovulation date varied from CD 12 to CD 17, so I often started testing early, usually at least once a day. If you’re getting, say, 4 or more days of positive results in a row, that can be indicative of fertility problems (PCOS possibly being among them). But, once it’s positive, it means: get down to business. ^_~
Tracking BBTs is dead simple. Try to wake up at about the same time daily (I usually got up around 7:30, but I would take mine anytime between 7 and 8). Record the number. During the first half of your cycle, temps usually hover between 96 and 98 degrees. After you ovulate, 97 to 99 degrees is normal.
If you’re just starting out, OPKs alone can do the job. I found that when I threw in BBTs, it more or less matched up with my OPK results.
Start brushing up on your diet AND your spouse’s diet. I honestly believe that it took 10 cycles for my husband and I to conceive because he eats like crap. We took a nutrition course together, and after tracking a few days of his diet, we saw that he wasn’t getting many of the minerals needed for good sperm production. I started sending him off to work with a multivitamin and tons of healthy snacks every day. Within 6 weeks, I was pregnant. Maybe it was coincidence, or maybe it was enough to finally boost his count up enough.
If you aren’t pregnant after a few cycles, maybe consider doing it every-other-day (with, ahem, no “activity” for him in between). Given that we already feared he had a low count, we started doing that and…of course…”boom.”