Lock Screen Question

I use S'mores, slidejoy, and screen lift. I've made $1.75 in a month on Slidejoy, $3.85 on S'mores, and less than $0.60 on Screenlift. Is this common? Is there something I could be doing wrong to earn this little from screenlift? If the earnings for screenlift is that low, but still with a constant lockscreen, I think I'm just going to uninstall it, that ones not really worth it for me.