is climbing a bit like mtb in that you dont realise how expensive it is until you’re well and truly hooked?
Depends. Indoors you don’t really need much more than shoes, harness, chalk bag, belay device and a karabiner. Buying that lot brand new is probably in the region of £150 – £200.
Outdoors things ramp up a bit. Obviously you’ll need rope(s), slings, lots of karabiners, quickdraws, and a variety of protection then it’s probably around a £800 – £1,000. That sort of money would cover you for most things initially. Course if you were bouldering you’re back to just buying shoes, chalk bag and maybe a crash mat.
Take a look at needlesports for an idea of what this might cost you.