If you can handle the delay in shipping, I think it's the way to go. I haven't compared costs in a while but the last time I check it was far cheaper to print online rather than purchasing an ink jet printer and printing from home.
There's also the added bonus of not having to worry about color management settings when you print online. While most manufacturers have made this pretty opaque to users, there is still the opportunity for you to make mistakes or not get the best color possible from your prints.
With all that said, I print from home or in a pinch, I'll run down to a drug store and use their kiosks.