This must be a UK thing – picks don’t cost anywhere near that here in the US. One can buy backs of 100 picks for something like $5.00. At least ordinary picks – there are picks made from exotic materials that can cost a whole lot more.
Why do they charge so much? Because they can, and people (especially artists) will pay a nominal amount to believe that they’ve got a high quality tool that will enhance their playing. For a buck it’s a low risk investment.
Many Texas players use a peso coin for its hard tone of attack. If you’re a chord-banger who breaks a lot of picks, prowl the toy section for something you can carve into a mega-pick that’s too thick to break. Polypropylene, the bendy stuff, gives a softer tone. Experiment. Wes Montgomery picked with his thumb, for a supremely mellow sound. I knew a cat who played power chords with a whisk broom. He sounded like multiple guitarists.