I used it very similarly to you, but found it to be about $3.50 per day, or $100 a month. It wasn't worth that.
Try opencode go using kimi - its more than enough for most usecases unless you try something really stupid that you shouldn't be getting openclaw to do directly, like coding.
Z.ai explicitly allows you to use it with OpenClaw on their plans.
Couldn't you use it with a Codex subscription? Plus is $20 per month
My minimax has liberal usage at $10 per month, if you’re not looking for some amazing model.