Thousand
This kanji looks like and means the same thing as the radical, which makes it particularly easy to remember.
As long as you know the radical thousand then you know the kanji thousand as well!
せん
ち
None
Remember the thousand crosses you got stuck under while learning the radical 千? You're still under it. Then, suddenly, someone pops his head over you and says "Hey, I'll save you... but only for a thousand cents (せん). Go ahead and try to calculate what that would come out to. It's not that expensive, actually.
But, the problem is even though you have a thousand cents in your pocket, you can't get them out. You're stuck under all these crosses. So, your savior just shrugs and runs off, he won't help you anymore. Feel the desperateness of the situation to help yourself remember the kanji better. Hear the coins falling on the ground.