I've been noticing a couple of you asking in comments about decent quality yet good value brushes. EcoTools were mentioned by some commenters and while you won't get the choice you'd get from a pro brush line, the advantage is they're affordable, can be picked up at Boots, are created using recycled materials and are made from cruelty-free hair to boot.
Cheapy online brand Elf has also jumped on the ethical, budget bandwagon with its new Mineral brushes, which use antibacterial Taklon bristles that are 100% cruelty free and which can be used with cream or powder products. Handles are made from a source of sustainable bamboo, and the ferrules are recycled material too.
If you don't mind buying online then there are 12 brushes for face, eyes and lips and two kits making up the offering and prices start from €6.50; kits begin at €17.50.
Whaddya think? Would this interest you?