As for cheap OPKs most people either go with the Wondfo, or the Easy@Home brand.
I have purchased both to see if there really is much of a difference. Price wise, they both vary a bit with quantity.
Wondfo vs Easy@home OPK
Wondfo brand OPKs came in the mail with over a year expiry date sealed in a plastic bag. Included was a single page of detailed instructions. Wondfos were the 1st internet OPKs I used and I became pregnant with my son tracking ovulation with them. I have no complaints and have never had a questionable result or dye run.
I am new to the Easy@home brand OPKs. They came very well packaged in a box. They had well over a year expiry, detailed instructions, and a bonus app to track ovulation. They seem sturdy and of good quality
Comparing the two in action I used the same urine sample, and the same amount of time dipped.
The Easy@home OPK brand needed more time to draw up the urine, maybe two to three seconds worth. The dye on the test line seemed to be pretty equal to each other. The control line did seemed stronger and less dye run in the Easy@homes.
The next time I purchase OPKs my first choice will be the Easy@homes due to the fact the seemed a bit bigger and were nice to handle. But I also would not shy away from the Wondfos again because I was successful with my first pregnancy using them. I hardly noticed any significant difference in the end.