Inexpensive clip-on fan with good airflow?

I have a 4 x 2 tent, and my only fan is a ginormous 18" one. I want to get a fan that I can clip to one of the support poles, that won't take up a lot of room but will provide enough airflow to move the plants around so they develop strong stems. And I'm already over budget for this grow, so I need to keep the cost down. Suggestions?

Look at the other thread on the front page right now about oscillating fans. Any small clip on will work for your needs, I have air kings for my small mommy tent and I use one underneath the canopy on my 4x4. Lasko makes pretty decent fans too.