Cherry-pick your best source for any given piece, and don't feel compelled to pair like items. Vintage medicine cabinets like this one can be had for $25. Stripped and refinished, its original beveled mirror and beadboard back are details hard to find even in a $450 reproduction. Meanwhile, the granite-topped vanity, with classic flush inset doors and chamfered legs, was a $400 home-center find.
Bonus Idea: Reclaimed doors can go for as little as $10 but need to be cleaned, stripped, and shellacked.