I have done some research and found some of the best OPKs.

Digital tests -

ClearBlue is the best in digital ovulation tests. They have a regular one that detects your 2 most fertile days. 20 tests for $35.26. They also have an advanced digital one that detects your 4 most fertile days(10 tests for $29.88 & 20 for $42.97) I have used this one and it is amazing. Definitely recommend it!! No second guessing lines, you'll get a circle if your not fertile, a flashing smiley if your fertility is high, and a solid smiley ☺ if your at your peak!

Regular line tests -

First Response has 8 tests(7 OPK & 1 HCG test) for $16.98. A little pricey for regular line tests but it comes with a old early result test(not the new curved ones) so I think the OPK kit is worth it for that. Haha! But the OPKs worked great for me & had good reviews!

Another name brand is Answers. You get 20 OPKs and 1 HPT for $18.98. I haven't tried these ones but I have seen a lot of ladies on glow use these and the reviews were good also!

Also, Fairhaven - a company that sells amazing fertility products has some OPKs & HPTs called BFPs. I seen amazing reviews! The price is 20 for $14.00 and 40 was $26.00. The more you buy, the cheaper it is. You can buy as little as one to as many as 200+.

Now, comes the online cheapies..

Wondfo is the best brand. I used them one cycle and loved them! You can get 50 OPK & 20 HCG for just $21.99! & its such a good quality ovulation test, accurate, and affordable! Especially if you have irregular cycles and need to test 2x a day.

Another is Easy@Home. Its the same as Wondfo, 50 OPK & 20 HPT for $21.99! I've used these also. They worked great as well.

Now, I also seen on there, Accumed, had 50 OPK & 20 OPK for just $15.99! It had great reviews also, but unfortunately, I haven't tried them.

I would just like to add one more thing, I tried Equate(Walmart store brand) OPKs and I hated them. Its very hard to tell when its positive because both the test and control line always stays the same color, its just a little darker when positive. I wouldn't recommend this brand!

I normally buy ClearBlue digital the 20 tests for $43 and the Wondfo brand 50 OPKs & 20 HPTs. It lasts 2 months! Well the test strips actually last 2-3 months.

If you have experience with an OPK brand that you liked, post it here! But especially if you had a bad experience with one, tell us about it! So we don't end up getting it, haha. TTC is hard enough, than having to worry about this & that..