The Fit is not a car, it's transportation. Besides, it's too late in the game to worry about getting a new car to save fuel. Who wants their last car to be a subcompact?
Try doing the speed limit, taking off easier from a stop, slowing down gradually when you know you're coming to a stop, overinflating your tires, combining your errands into one trip, shutting the air conditioner, and eliminating unnecessary driving. Basically, you have to take all the fun out of driving in order to save fuel.
Buying a B-segment subcompact is the same as paying somebody to take all the fun out of driving for you; do it yourself and save some money. Besides, it's nice to have some power in reserve when you're driving, just in case you actually need it. A subcompact has nothing in reserve, it's always driving at its limits.
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"The genius of any slave system is found in the dynamics which isolate slaves from each other, obscure the reality of a common condition, and make united rebellion against the oppressor inconceivable." ~Andrea Dworkin
"If... the machine of government... is of such a nature that it requires you to be the agent of injustice to another, then, I say, break the law." ~Henry David Thoreau, 1849
That's right, bitches, TWO quotes!