As unorthodox as that may sound – time consuming hobbies really are a good way to save money. Just as anonymous said, "you[sic] are not out spending it on other things."

Obviously the hobby needs to be scrutinized. When I used to crash my electric R/C helicopter or drive my gas powered T-Maxx around at 45+mph … I tend to break something when it careens into rocks, trees, etc. Not exactly as "cost saving" hobby. But sitting on your couch all day playing Halo? $0 essentially (unless you’re ordering pizza all day to complement it).