Oops! paint is perfect for many applications. I use it mostly for set designs and scenery backgrounds where I need a lot of paint. There are endless uses for this paint, especially for kid's art projects that are more about the experience not the end product.
If what they have in stock is not to your liking, and you know your color mixing, you can ask the guys that mix the paint to add pigment to the paint to get closer to the color you want. They usually don't like to do this, but ask nice and they will. Be patient, it is hit or miss most of the time. You just have to look for the little oops! paint shelf every time you go.
It is really important to read the can. It might be oil or latex or even stain. I would not recommend it for something really special or of great value. It is rejected paint after all.
I was thrilled last week to get two gallons (two similar shades of blue) of outdoor paint. I got a 5 gallon bucket and mixed the two gallons throughly together. Now I will have enough to brighten up my back patio. A fresh new look for $10 is hard to beat.