The room I used was the breakfast nook in my house and it is 7’6″ long, 6’10” wide and 9’13” high. The storage unit we made was from wood found in my basement and kickers from Home Depot (for the legs and support) as well as 2 hallow doors from a local Construction Junction for the shelves. The unit itself ended up being 5’6″ long, 1’6″ wide and 5’7.5″ high (there’s 2.5′ of room between each shelf).
With the more than helpful lending hand of my awesome friend and tools like a strong power drill and a table saw, we build what’s below. You may need to buy screws if you don’t already have some (that’s where it might get pricey). We lucked out having found or being in the possession of most of the materials.
My friend gave me the below hook (handy hook) to hang up the bikes. I bought another but ended up only having room to hang up one so used that for the car bike rack.
Inspiration (some other ideas and instructions for building storage shelves):
DIY Storage – How to store your stuff
DIY Storage Shelves