I've used various Escort (Now Valentine) Models since getting my license at 16, about (gasp) 14 years ago. I drive about 15,000 miles a year, through city and country alike, speed pathologically, and have never gotten a speeding ticket while driving my own car.
They're so confident in their product that up to a certain speed above the limit, they'll even pay you the price of your ticket if you get one.
A new one will run about $400, but I'm sure you can get a slightly older model for much cheaper.
Just don't be like this guy:
"In May 2003, on the San Francisco to Miami Gumball 3000 Rally, the first CCR in the United States received the biggest speeding ticket (in terms of speed) in the world; 242 mph (389 km/h) in a 75 mph (121 km/h) zone somewhere in west Texas."
http://en.wikipedia.org/wiki/Koenigsegg