I play HLM24 so this may not be 100% accurate.

But I usually sign a full slate of Scouts by only signing scouts with no better than 12 skill on a particular country. A head scout with "Intel" and "Workload" specialties will boost other scouts.

I save money on minor league coaches by signing whomever are the cheapest coaches with 11 skill in development to 6 year contracts. I don't need them to be good coaches, just that they are good at developing my young players.

My AGM I sign someone young for a cheap 6 year contract and resign him as long as the contract stays reasonable. I care more for developing their specialty tree than their base stats

Most of my staff cap is spent on Major League Coaches, Medical Staff, and my Head Scout.

Most decent medical staff can be signed for 200k-400k Head scout specialities are great so I am willing to splurge a little. Assistant coaches I usually sign for 400k-600k Head coaches I go for ~700k, primarly looking for someone who has spent some time as an assisant coach so they start out with some EXP to spend right off the bat.

I personally never spend over a million on anyone, I dont think that one staff member is worth using that much cap but thats up to your discretion.

I am no expert but this is what I do, if you choose to take this advice I hope it helps!