For me it's a pay-as-I-go approach....I started with this 24 x 36 x 14 high....in 2008 I had it built for $6500.00
I first added a 12 x 36 lean-to one one side...
now I'm in the process of adding another 12 x 36 lean-to on the other side along with a 20 x 36 on the back.