Steel frame road bikes (especially vintage) can be picked up for a song using ebay, craigslist or facebook marketplace. Also if you make nice-nice with your local ride groups and bike nerds, you may be gifted vintage bikes as people get their carbon fiber beauties and look to empty their bike stable of older blood.I used to have a steel frame Diamondback road bike. It wasn't the fastest, a bit on the heavy side. But man was it a dream to ride casually, maybe 15-30 miles on a weekend. No other material compares for ride quality, IMO.
Stolen from me, at a time when I didn't have a car either. I've been thinking lately about buying another.
That's how I've come in to owning both my steel frame race bike and my aluminum frame touring bike.
Centuries on steel are fun, if the road doesn't pitch too much. And when it does, having a good gear ratio close to 1:1 really helps.