My staff consists of:
9 Class B coaches, all with 9 pucks in the skill they are training. 7 of them have a salary of $6,000 USD or less (one costs $6,310, another $7,340 - the last one is my power coach, 9 puck power coaches are close to impossible to acquire, so I haven't been able to replace him with a cheaper one). These coaches train my seniors.
5 Class C coaches, all with 7 pucks in the skill they are training (power/shooting/checking/keeping/stamina). These guys cost me between $2,930 and $3,700 USD per week. These train my youths.
I've built up this staff for as long as the new coach system has been out, so well over a year. It takes a long time bidding on new coaches (and firing the old) to get them this cheap. Since I rely on training my own players as opposed to transfers I've put a lot of thought into what coaches would give me the best training value for money, and I think this setup is close to perfect.
For 14 coaches my weekly costs are $71,179 USD.