The test strips, at least when I've put them head-to-head with the liquid, were dangerously inaccurate. The strips would test at 0ppm, and the liquid would test at up to 0.25ppm difference...if that was 0.25 to 0.5, that could really start to harm a fish quickly, and could really throw off your cycling steps as well.
I tried the strips at first too, and later realized I'd just wasted 10$ I could have put into a liquid kit...never again, lol! :)
Also, it's almost a one time investment. Once your tank is cycled, you only have to check things out occasionally, and so that test kit will last you forever. :) I've got one I've had for a year, and it's still 2/3 of the way full, and that's after having cycled and started six separate tanks.
This one is 24.00 **with** shipping:
I hope that helps!!