it would cost you less to replace them, in most cases. Also, you can do one of two other things as well:
1) use parts from the laptop to repair the computer (it can be very tricky, so I wouldn't do this)
2) if the laptop is new enough to have USB ports, you can get an adapter and use your computer keyboard.
I'm sure there is someone on here who might be willing to donate, but I'm saying just in case...