How are the dollar store tests?

I've used these a few years ago with my other kids and got early bfp's, how are they working now? My last af was 9/4, I tested 10/2 with a bfn, but I still haven't gotten my period. I'm a little low on cash right now, but if the dollar store tests aren't what they used to be then I don't wanna keep wasting money there.