Under the table special deals

Ron made a nice wood stove out of heavy plate for the Elmira Hunt Camp, he said it took several days of shop time to fabricate, but only charged cash for the materials(no bill, no receipt). I got the impression that this is common practice here. So what if it never gets reported as income, those yearly vacations in the warmer climates aren't getting any cheaper.
If your project is not deductible, it wouldn't hurt to ask about under the table to save GST and PST and get a break on the labour like the camp did.