Re: Give it away.
One of the problems with that idea is, I fear, access to the deep space communications network. You can't just point a 1 meter dish in the general direction of Mars and get an IP connection going. You need access to NASA's network of dishes dotted around Earth. And they're pretty busy, and expensive.
However, my view is that whilst there's a prospect of the Martian marauder still doing useful science, then it would be a hideous waste of money to not use it. Arguably these two trundlers, and Curiosity too, represent astonishing science (and public) value for US taxpayer dollars; they've gotten far, far more for than anyone ever bargained for. The original project Balance of Investment report is utter toast; the costs account is so heavily outweighed by the delivered benefits account those responsible should get medals.
Really the answer should be, build more deep space communications dishes, and get even more value out of the missions that are running, and out of other future long lived missions. There is an argument that international collaboration on that network is the way forward.