Massachusetts Premier Buyer Broker
When I bought my first condo in Washington, D.C., back in 1974, garage spaces were available for extra cost. I forget what they were going for at the time--probably around $5,000. When I bought my second condo in D.C., back in 1978, I paid $60,000 for the condo and $6,000 for the parking space.
The practice arose because parking spaces are limited. And a developer can make more money by selling parking spaces separate from the condos.
Hope that helps.