I offset the carbon emissions through Terrapass (http://www.terrapass.com/). It's not perfect, I know, but I can't afford a Tesla at the moment without liquidating my TSLA stock.
Since when are services built on sound science "indulgence-style"? It wasn't like I drove to Florida on a vacation; I was taking care of a family member. I'm not supposed to go because I'm releasing ~2 tons of carbon? Bah.
There's nothing wrong with driving far distances, it's just that money negating pollution is silly to me, as incongruent as a tithe forgiving sins. You can't just wring automobile emissions out of the sky, and a donation doesn't change the fact that the extra car on the road causes other cars to slow, producing more emissions, increasing demand for road infrastructure and such.
Total cost to offset ~2 metric tons of CO2: ~$20 (http://www.terrapass.com/shop/)