We bought a used Trek years ago and it was like night and day compared to our old running stroller. Do your best to get something that is from a legitimate brand that looks like this:



20" wheels, tracking adjustment, and aluminum.

Kelty makes some:

http://www.sierratradingpost.com/joyrider-20-jogging-stroller-by-kelty-kids~p~85906/

There's other brands, but I can't recall names right now.