I agree with the Draino being cheaper way to do it. If you take the tests at different times of the day and/or after eating different things you might get different results. When trying a few different tests I got boy and later girl. No clue what were having, were getting a second try in 3 weeks.
I took a couple of those my first pregnancy and never got the same result. Cheaper way to do it is the Draino test. If you look it up online its the same concept. :)