Affordable sustainable clothing… does it exist?

How do you become more sustainable in your choice of clothing? My clothing buys are 90% second hand and have been for years, but I’ve recently been looking more into sustainable fabrics. I still have a lot of polyester/nylon clothing in my wardrobe and knowing that the fibres are leaking into the water system makes me feel horrible every time I wash them. I would love to start phasing them out and investing in some more sustainable clothing. The only issue with this is cost. It’s difficult to justify spending that much on an item of clothing when we’ve become so used to cheap clothing stores and fast fashion. What clothing brands would you recommend? 👚