Cheap pregnancy tests???

Megan • My DH & I have been together 1 1/2 yrs. I brought 3 kids & he brought 2. Just found out #6 is on it's way!!!!!!!!
Ok so my AF is 9 days late... I'm having several symptoms etc and I really do think that I'm pregnant (I have 3 older children and I feel very much the same as I did with them) but I've taken 3 tests and they have all come back negative... The last one I took was 3 days ago. All the tests are the $1 tests from the Dollar General though and I'm wondering how accurate they are. Do I need to buy a more expensive test or just keep waiting? I'm so lost! But I don't want to just keep throwing away more money on tests for nothing... Any advise would be great!