The cheap strips from Amazon are perfectly good as long as they are pink dye, not blue (which are notorious for false positives). You can buy them in bulk - these are $8 for 25, $12 for 50, and $17 for 100. They’re the exact same thing as the more expensive tests, just slightly less sensitive so it may take a day or two longer for them to show as positive.

Here is the link to the ClinicalGuard ones!

The only "issue" I've had with them is that, one time, it came back inconclusive. I just took another one when I was ready and all was well, so not really an issue at all! My friends use them as well, we haven't gotten any false negatives or false positives thus far.