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.
Couldn't you use it with a Codex subscription? Plus is $20 per month
Z.ai explicitly allows you to use it with OpenClaw on their plans.
My minimax has liberal usage at $10 per month, if you’re not looking for some amazing model.