I have done it numerous times, the service Ml shows up, has about 10 batteries, plus a tool box. They change the battery, recode the radio, resync the windows, take the old one, and usually are there in less than an hour. When I called my service manager about coming in for a battery, he told me im crazy becuse then they have to charge labor.
The roadside service program is great, it is a lifetime of your vehicle program, they do charge for things they install. I had a flat and could not get the rim off, they will put on your spare no charge, I dont know about fuel, they tried to replace my fan belt once but the tensioner was bad, so they called a towing company and had it hauled to the dealer.
As I said $180 from Long Island, was a litle high, it is typically in the low 100s, yes you can go buy a battery and do it yourself or go to Sears or Pep Boys some people are just bargain hunters