Where do you buy your ovulation test stripes from?

🙋🏼‍♀️ hi

I’m just curious to see where everyone gets there test stripes from and experiences using the eBay ones I purchased the 100 pack and manage to get a distinctive two lines but the test line is never ever darker or as dark at the control stripe what can this mean am I testing at the wrong times? (I test normally around 10:30-11am and 2:30-3pm)? Help please