Found a decent paint for less than a mil ?

I used the black to paint my nephews neon and then I used what was left over on the faded roof and hood of my Chrysler Lebaron. I works great. But after a few days (yes I said days) it starts to orange peel. I have not experimented to see what Iam doing wrong. But, it seems that it dries to touch and then it continues to dry for a week or so and keeps crinkling up. Any suggestions would be appreciated. It is easy to use.