You have to be a USFSA member in order to register as a coach, so I go through the Club. I edited my original post wrong: the "Senior" Club membership is $125, the "Family" Club membership is $210. We have three active skaters, so we have a family membership.
Our membership fee is reduced based on how many service/volunteer hours are earned the prior year. It's complicated, but I think our out-of-pocket cost last year was $155 for the family membership. Since the girls tested/competed, they also received skater support checks.
The USFSA has NOT lowered the cost of the Coaches' registration; the publications say it's $40, but when you go to pay, there's a service fee added on, raising the price to around $44. I rounded, sue me. I was using my budgeted numbers for the year.
The same is true for the alternate Basic Skills Instructor membership: the stated cost is $30, but there's an additional service fee added on at checkout. However, Basic Skills Instructors (who are not called "coaches") don't have to be USFSA members. They just need a Basic Skills Instructor membership from each BSS program, which costs around $12-15 annually.
Liability Insurance Options:
$94 - USFSA
$94 - PSA
The ISI offers a combination Professional Membership + Liability Insurance for $170.
I believe Sk8Dreams said that the coverage varies between policies, so coaches have to check to see if the ISI coverage is sufficient.
Our rink/club are USFSA-only and I am already a PSA member, the PSA insurance is fine. It's less brainpower to just go with the flow and get the PSA policy. There are no active ISI rinks near me; one uses the curriculum but has no competitions or competitors.
Because I present skaters for USFSA testing, I have to be at least CER-B, but I chose to take the extra course and study IJS since the standards it sets are being brought down to the 6.0 competitions. (Spins should have a minimum of 3 revs in position, jumps should have difficult entries, etc.)