This is nearly $400. Cooper instruments doesnt seem much cheaper... Any ideas for more sources of load cells?
Keep looking, Im confident you can find one for under $200. If not, you should consider making your own. Since you do not require high precision and only one axis, it shouldnt be too hard.
Also, how would i be able to use this with a microcontroller? Are the voltage outputs large enough? Will an op-amp circuit raise the voltage enough?
I use an op-amp fed into my microcontroller ADC.
The rating on the site is 2mV/V. What does this unit mean?
That means the maximum output voltage for 1V supply power will be 2mV. So lets say you supply your load cell with 10V, it wont output more than 20mV. Using this knowledge you can calculate how much gain your op-amp needs for the microcontroller ADC to get a good reading.
You will also need to calibrate your sensor - plot weight vs microcontroller ADC output and develop an equation using excel. If you are lucky, your sensor will be linear (mine are), and it wont un-calibrate itself over time.
Oh, almost forget. Since your sensor will have a repetitive load, spec the sensor for 2x that expected load. This will prevent fatigue failure of your sensor.