How to shop Locally from online stores.

How do I justify selling online to buyers from across the country while I emphasize shopping locally?

I had an interesting conversation with a friend on Facebook yesterday that got me thinking. We were discussing the merits of shopping locally versus saving money at a big box store (BBS). My reasoning for shopping locally was similar to what is discussed on the 3/50 Project, in a nutshell, that for every dollar you spend locally, 68¢ stays local in taxes, revenue, further spending etc., compare that to 43¢ at a national or multinational corporate chain. My friend said that they shop at a BBS to save money for their family. Now I, not having extra mouths to feed, cannot judge or pretend to know what it is like. But having family members and friends who work at BBSs I have seen first hand what kind of demeaning conditions under which they work on a daily basis. This, coupled with having made many friends of local business owners has kept me shopping locally for quite a while.
Then our convo took a turn. My friend asked me "Would you not sell one of your homemade books to someone in say Colorado? London?" I had to really think about the implications of my selling online to people across county and state lines. Am I perpetuating a behavior that is undermining brick and mortar stores as badly as the BBS?
I have seen a few stores go through some rough times, citing their inability to compete with online and BBS prices. 
So I took an inward look at what I am doing, starting with my shopping habits for my business. I buy all of my materials at locally owned, brick and mortar stores unless there is no local source for what I am looking. So far that hasn't happened. If I can't find it locally, then I probably can do without it. If I absolutely need it, then I can ask a local merchant to special order it for me. If I still can't find a local source, THEN I will look online. This brings me to another interesting conversation that I had with a local art store owner who told me about the 3/50 project. We were talking about shopping locally and how important it is, both of us preaching to the choir. Meanwhile I mentioned to her that I am getting into paper marbling and that I would love to get some into her store. She told me she wasn't interested because she could get handmade paper online so cheaply. She showed me a handmade looking paper sample binder of the company she orders from. I asked where they are located and without skipping a beat she told me "China." China?! I'm not sure what I am trying to get at here, maybe that even those with good intentions get caught up in that bottom line? I don't know, but what I do know is that I am buying locally and only as a last resort do I go to the internet superstore, and I encourage you to do the same. If you can find a handmade journal or book locally, buy it! If you can't, I'll be here holding up the store, my doors are always open and rest assured that I am doing my part to thinking locally in a global marketplace.