"Lowe's" has some that screw in and match the threads on the originals - but the shaft is longer than the originals, so you may want to cut them... I didn't cut mine, so it just takes longer to unscrew 'em...
The good part is that they sell for $4 apiece or so...
Yeah hit a home depot or lowes or better yet a local hardware. Just bought 4 last week at home depot, but they are like the picture in post 2, 2.75 each