Most co-op’s pay for themselves in terms of housing/room/board/food. Nearly all of them are paid. Unpaid co-ops are in the incredibly small minority and are usually in hyper competitive fields like clinical psychology or something. Good ones will pay for more than room/board. If you go out of Boston, many co-ops will offer free housing as part of the job. The rule for financial purposes is to expect that you break even on co-op - any extra is nice but not guaranteed.
In terms of worth it, I would say easily. The experience, the ability to really be able to try out your job before committing to it and feel confident in your career choices, and it doesn’t cost you any extra in terms of tuition/housing. You’ll probably make money on it, especially in certain fields.
What is your intended major/field?