Inexpensive force sensor - 100N

[Rob]

Can anyone please point me in the direction of a supplier of inexpensive
force sensors. I am setting up a small science kit and am looking for
something around 100N / 10kg force. Cost is a major consideration, yet I
also don't want to spend a heap of time hand making a sensor.

Operational principal is not important - can be strain gauge, hall effect,
conductive rubber or whatever.

Thanks for any advice
Rob