Why are hobbies so expensive!

I love to knit, but really don't want to use man-made fibre - acrylics etc - from an environmental standpoint. Plus pure wool is so much more pleasant to knit with and to wear. Considering farmers get nothing (or have to pay) for their wool, why is it so blooming expensive to buy? Particularly British wool. If I pay upwards of £7.50 for 100g, then a decent sweater is going to cost around the £60 - £70 mark, more if I use more than 1 colour. Wool jumpers last a long time, I still wear an Aran I made in the 80's. Maybe I need to find a new hobby....something that doesn't require the purchase of craft materials or equipment...

For patterns I scour the internet for free ones or make up my own. SC, have you tried searching for a free pattern for whatever you are going to make?