Below a certain price you are buying problems. But the threshold for a genuinely good bike is lower than most people think. Two hundred pounds buys a used bike better than a new one at five hundred. The sweet spot sits between £150 and £400 on the used market. Under £100: old rigid mountain bikes from the nineties — Raleigh, Dawes, Specialized Hardrock. £100-200: Carrera Crossfire, Decathlon B'Twin. £200-400: Giant Escape, Trek FX, Boardman SLR. This guide covers the best bikes at every price tier, end-of-season sales, ex-demo deals, cycle-to-work savings, refurbished bike charities, and what to avoid (Amazon specials and stolen bikes).