I'd say 85% of my kit was purchased
But I'm lucky because the girls at MUFE like me, one of them is closer to be a friend than just a MUA. We've been to New York together last may for the Makeup Show. She gave me a lot of things she had in her own kit, like a brush belt, some pressed powders, foundations, a kabuki, pigments and such... and at the counter when I buy she always make sure I get goodies for my kit.
I guess it helps having a friend in the industry, who believes in your carreer.