How do you distinguish between "keeping you from switching" and "it being inherently difficult to switch?" If you buy an expensive car that only runs on expensive and rare fuel (thereby restricting your choice in fuels), is the free market somehow violated? If you buy a Gillette razor that only works with Gillette blade cartridges, is the free market violated? I find the distinction rather fuzzy.

Erm, how is that different than food? You can't choose not to buy food, so would you also consider that not to be a free market?

You can grow it or hunt it.

[edit] Not that I think that the global market for food to be a free market.