In some parts of the country, that's easier said than done. Here in the Tampa Bay area, high-end vintage bikes in "restorable" condition are extremely rare. When one does surface (especially in large or small sizes), its usually priced so high (even after haggling) that it would be significantly cheaper to buy one already restored. For someone who just wants to have a "fun" project (and isn't looking for financial ROI), the low-end models from quality vintage brands can be a good starting point that limits your overall investment and still results in a fun recreational bike.