It's cheaper to have a company to do it. I worked for a lawn care company last year and we got our granular by the pallets so of course it was cheaper for us because it was purchased in bulk. Put down a slow release with a high nitrogen to get that better color.
Don't go with TruGreen. We took over many of their customers. We had a new customer that I started doing his lawn about mid summer last year. He switched from Tru Green. It looked like crap. Weeds everywhere, bad color, and the grass was pretty thin. After just three applications, I had that lawn looking beautiful.
DON'T FORGET TO WATER!