How much do I need to spend on a good adult bike helmet?

Specialist-community consensus on r/cycling is that the $50-$90 range gets you a MIPS helmet with protection comparable to $150+ models, with extra money mostly buying lighter weight, better ventilation and nicer straps. Budget picks like the Giro Fixture II and Schwinn Thrasher are repeatedly cited as safe, certified options for casual and commuting use.