No, it should be an if statement. The /inc command will increment (increase) the value of a variable by a given amount (or one if no amount is supplied).
You need to compare the value of the person's account (which I'm going to presume is being stored in a variable) with the value of 100.
If the value of the variable equals 100 then send the Sorry message.
I know this isn't coded, but it looks like you want to try to code this on your own, so I've just explained what it is you need to do, without actually showing the code.
