Yes, they do have alot of ads. Think about it though, for what you pay for the magazine, its a heck of a deal!
I was in a group that looked into publishing a magazine for nationwide distribution. The cost was way more than I imagined. I don't know how some low volume magizines stay in business. That being said, Moose River has to pay for the printing and distribution cost from ads, they do not generate any revenue from subscription fees.