The Miracle Maker 7 Day Miracle Growth is really good too. I have used it as well pretty frequently but sad to say I have not left my nails natural and bare for seven days to see how much my nails would have grown with it. However, I have done so for at least three days and saw a pretty good difference in how strong my natural nails became and also some growth to them.
I would recommend these two and I have bought them both numerous times. I found these at my Dollar Tree, but I am sure Walmart would carry them as well.