Query about glass cutting

I am an owner builder and as such have glass needs for my windows.
If I have a large piece of glass is it feasible to cut that glass down
in size and use it for a windows?
Would this be cheaper than outright purchase of glass precut to the size
required?
I am assuming that pretty much any qualified glazier could do this (if
of course it is doable and worthwhile)?
I have the opportunity to get all the glass I need FOR FREE so this
information would be good to know.


This was the only glass newsgroup I could find.
I tried to call glaziers from the yellow pages but all I got was the
runaround. It seems if you aren't ordering a broken window to be fixed
or something similar then you are wasting their time. Any of these
companies that would have put me through to someone in the know would
have most likely had all of the business when it happens