I own and American Tower site in Vallejo CA. Current rates are $1,880 or so. There's a 5% escalation per year. A couple of years back they sought a 30 year extension and provided a $25K signing bonus.
Last year they once again (maybe a dozen times so far) tried to get me to cash out and give them a free lease for eternity . . . this time offered over $200K. They said that they didn't want me to be stuck with a naked tower as some of the co-locators were thinking of moving off. I told them I didn't mind if they all left . . . as my lease says the building and tower remain and revert to my ownership. They backed off.
This site has been there since 1996, BTW, and started at $600 a month. :c)