Supporting your local model shop is all well and good, but a lot easier if your LHS is large and well stocked like Rails or Hattons.
My local shop is Janes Trains in Tooting. It's an hour round trip on my bike, nearer two hours on public transport. Probably quicker by car, but local parking is virtually impossible.
Jane and her team are wonderful people. Very friendly and knowledgeable, and would bend over backwards to help their customers.
But it's a small shop and the ranges held in stock are of necessity, limited. If I was after the latest marvel from Bachmann or Hornby, fine. But if I'm after GWR spear fencing in O gauge, or a white metal wotsit to correct my thingamybob, probably not.
There must be tens of thousands of low price items aimed at railway modellers that a small shop would not stock due to space limitations and too small margins. By shopping on line I can have my hearts desire within a few days from anywhere in the world.
And I'm sorry, but on price, I'd rather as much of MY money stayed in MY pocket as possible. I cannot justify 'throwing away' a wad of cash just to help a local shop make more money when my chosen 'box shifter' has the same loco 20% cheaper.