Confused- BFP or BFN

Hey guys- I took this cheapo kind HPT and at first I saw one line- so I left it there and when I got back home I saw 2 lines had appeared. The test says do not look at the result after 10 minutes. . I took another test but again, it's only one line. Is it time to buy a more expensive test or does this seem to be somewhat accurate​? AF is due on the 13th.