Jason, the spary on foam i.e. sprayed into open stud bays is not a DIY project. The kind that you spray into closed bays is best avoided since it is very difficult to get complete coverage. Infrared camera scans show that it mostly tends to setup around the hole leaving large areas uninsulated. It's not that it can't be done right, it just usually isn't. Consider blowing celulose. Densely packed celulose will perform as well if not better than foam, and it can be a DIY project.