All of the City of Bristol museums and art gallery’s are free to anyone at all(there are lots of sites round the city). They were forced to charge for a period some years back and the place became empty of visitors (I knew one of the security staff there).
I hope the Banksy display is better than the replacement Egypt display – which went from a load of interesting artefacts to mainly a bunch of computers showing stuff you could internet at home. Very sad, that the curators seemed to view computer images as more valuable than seeing the real thing. Still, these are the people who wanted to demolish one of the few remaining historic dock buildings to build a trendy new museum 🙁 Only a massive public outcry stopped them.