I hear that! I have done some for friends just to show them what is involved. They usually give me around $200 even if I don't ask for it.
Helps pay for the parts washer solvent and shop towels. One guy in the military bought a '66 or '67 Coronet, and that trans was a mess.
Had a cheap bolt in sprag and the PO tried bolting it in with the 1/4"x20 bolts unsted of the correct 1/4"X28, and broke off three of the four bolts in the sprag. The PO also tried installing a cheap plate type shift kit, so the valve body has two plates, the stock one and the shift kit one.
Also, no kickdown on the trans.
After fixing all that and rebuilding the trans, I also made him a deal on my old 10" Dynamic converter and Lokar Kickdoen kit that I happen to have laying around because I went to a Cope MRVB and Ultimate 9" converter.