All tests will eventually show your hcg. Dollar tree are a buck. What you are wanting it to do for a buck is what it will do. It will test the hcg in your system. Will it show you early? Will it show you today (because we know you want to know right now this very minute ;)? I don't know. But eventually, if you are pregnant, it will work.
I wouldn't spend a lot of money on pricier brands. Wait a few days, keep taking care of yourself (take your vitamins!) and let nature work. If you don't start your period, take another test. If it is negative and you still don't start your period, go to the doctor.
But whatever you do, don't stress and worry over becoming pregnant. ;) have fun at it!
Good luck!