Spray paint doesn't stick to non-porous surfaces very well. So when you try spray-painting plastic bins from Dollar Tree, it will look like you are painting water (a lot of it!). The best thing to do is to paint the DIY-painted plastic bins with a good primer, and then spray paint it with an exterior spray-paint. While it is possible to spray paint the Dollar Tree bins, it's not easy, but it is not impossible either. It will take a lot of effort and time. Also, it's very likely that you will have to repaint it more than once. So if you are looking for a DIY project that will give you a lot of bang for your buck, then this is not it.