There are too many ten to fifteen year old small cars on the road that get 40+mpg that I simply can't recommend anyone buy one of the new ones that strain to do better than 35mpg.
I'll take a SOHC 96-99 Saturn, a 1.5 liter 97-02 Mirage, a 1.6 liter 95-99 Sentra, or a 96-00 Civic HX over anything sold today. $1500-$3000 will buy one and that's a down payment on anything new. Save your car payment money for any repairs or upgrades or whatever.