which ipod should I buy if I want to run with it and don't have a lot of songs?

I would recomend the Ipod shuffle. If you are running then you don't need to see what is playing and the shuffle is really easy to hook-on to your waistband or sleeve. Also; {just like all ipods} you can buy a special thing to rap around your upper arm to hold the ipod so it is out of the way. The only down-side to getting a shuffle is that it does not have the "Nike + Ipod" feature. This tells you how many calories you burn..etc. You can even make your own work-out play list. To get this you have to have an ipod with a screen.

iPod shuffle is jaw-droppingly small and enormously colorful in black, silver, pink, blue, and green. And even more brilliant, the VoiceOver feature tells you what song is playing and who’s performing it. It can even tell you the names of your playlists, so you can easily find one to match your mood. With VoiceOver—and with the controls conveniently located on the earphone cord—it’s even easier to navigate your music. And you can browse without taking your eyes off your run, your ride, or whatever you’re doing.

You can also consider using an armband. Rugged and durable, this case adds both grip and protection to your iPod in one shock absorbing layer. Uses the adjustable armband to secure your device while your workout.

You should consider buying an ipod shuffle. It's small and made for joggers!  The Ipod shuffle has 2gb of memory which is around 1,000 songs for the price of $59. They also have various colors. To purchase one : http://www.ebay.com, http://www.ipod.com, http://www.walmart.com, http://www.target.com. Hope this helps! Thanks for asking!