There's also a guy close to me selling similar Cannondales for $550+
That's probably me, but the 'Dale in Philly can't hold a candle to any of my restored bikes. Start by buying a decent project bike like that for $300, then add $100+ for consumable parts and more than that for a 1st class powder coat job and decals, and...well you get my point.
Agreed, though for the DC market those prices are reasonable, considering that the seller took a little time to clean 'em up. Down here they would probably still have dust and grime on them. And cooties.