if we are talking about UK. I know 50% fail the IR(total fail, or partial), and have to pay 6 hours retraining plus retest. so count 6000-7000 pounds.
i met guys who had to leave the school for several months cuz they were short of money.
for the cpl vfr, no big deal, 1-2 more flights, and redo the test.
generally i would count 30% over your general training. if you training costs 50'000 pounds by ex., count 65'000 pounds.