At what point does paying for AI APIs become too expensive for a solo developer?

I’ve been using AI APIs to build my projects but the monthly bills are starting to add up. Running open-source models on a cloud server seems like a good alternative but GPU costs maintenance and idle time make me wonder if the savings are actually worth it. I don’t want to spend hours managing servers just to save a few dollars. For developers who’ve made the switch did hosting your own models really reduce costs or were API calls still the better deal?