J.B.
Both of my boys have loved the ride on-scoot types of vehicles. They can sit on them and scoot with their feet, and they can also push them everywhere, which is what happens most. The play lawn mowers are a big hit as well! You can find any of them at Toys R Us, Target, Walmart, etc.
Oh -and get a Little Tykes car! They LOVE to ride in them and push them! They're Fred Flinstone mobiles -totally foot-powered.