Check with your condo documents, but I believe you can. In a condo I bought in Atlanta prior to moving to Fla. I sold the parking space as did many of the other owners. The space in Atlanta downtown location was work ten thousand dollars. We also could sell the storage bin space if we didn't want it. OR we could rent it out to others. Now that may be an option...rent the space, keep ownership. That way, as it increases in value, you can up the rent. But there again, have a legal document outlining the arrangements.
But don't guess at it, either turn the question over to an attorney or discuss with the manager of the complex....or read over your documents prior to making a mistake should they not permit such sales.