I am lucky enough to have my dream shed, it's a double garage really but it's never had a car in there. There are just three bikes at the moment. Being a builder it didn't cost me anything really, just my time to build as most of the materials were 'surplus' on sites, the rest came from skips. It's a great 'man space' to escape to but the wifey did slip in a washing machine and
chester frezzer.
It's great having loads of space, room for my building tools, bike gear, multigym & exercise bike. Loads of storage (old kitchen units) means it doesn't get too cluttered and I find my 6x3 joiners bench is also great for working on the bike and base for the lads pool table

I put some old carpet tiles down a few years ago, they make the space feel much better.