Oh yeah the bedrock per token usage is crazy money compared to using a plan. I just about manage to keep under the £90 limits on the Max plan, have occasionally needed to go up to then £180 one.Using AWS seems to almost always be more expensive than just buying a plan, and I think they're using Opus by default now.
Opus vs Sonnet will probably also be pretty situational, although I think Opus will more often than not, be the more expensive option. For certain tasks, it might use fewer tokens as it's a better model, but needs to be meaningful to actual get it under Sonnet, which might use more tokens for less cost.
Probably gives you a reasonable idea of the loss-leading that's going with these providers. On a busy week, or when I'm doing lots of heavy refactoring, I'd be burning thousands of dollars worth of tokens a day.