Forget looks and popularity
There's a tendency in the used-car marketplace to put huge price premiums on certain cars just because they happen to be popular. If you want a better deal, explore the long-term quality of those vehicles that have the toughness and build quality to outlast the hype.
There are a slew of models out there that have great owners and excellent long-term reliability. As it happens, they're unpopular because either the brand no longer sells new cars (RIP: Pontiac, Mercury, Saturn, Hummer, and Scion) or the specific model name is no longer sold in the new-car market (so long, Buick Park Avenue, Mitsubishi Galant, and Chrysler Crossfire). The Long-Term Quality Index is an excellent source for finding these gems of opportunity. (Full disclosure: I run the LTQI, and while yes, that's a plug, it's still a damn good resource chock-full of data sent in from hundreds of thousands of mechanics from across the country.)