Tool cost analysis

Some time ago (I’m, not sure how long ago), I read (I think it was on
Orchid) some tips on how to analyze tool cost/expense vs.
profitability. I’ve searched the archives but with no success. If
someone on the list can explain this I would greatly appreciate it.
I receive the Orchid list in the digest version so to ensure I get
the please e-mail me off line with tool cost as the
subject if you know of this, or know where I can find
this Thank you.