trentonlf: When you say shop it sounds like you mean the "shop" has a storefront and you go inside to see the shop owner behind a counter and you purchase items from them? Versus a random peddler on the street or in the wild who has items for sale?
misteryo: After his last reply, I think he must mean a shop you access from anywhere in the game world and you are "transported" there - as if the shop is another dimension. Bingo.
misteryo: Still not a meaningful distinction to me, but I'll be darned if I can remember where I first encountered this ...
What has actually prompted me to ask this, is that (at least that's my impression, I have to say that I'm not really into modern games) in-game shops are nowadays a boilerplate concept in modern games, like your beloved quicktime events and ... for the love of god ... downloadable content. But I remember when Kingpin came out, it seemed like something new to me. This made me curious when this all started. Even though RPGs may have had a similar concept since the beginning of time (1979 is actually not far from the beginning of time, at least on Unix systems), the introduction of in-game shops into other genres happened much later. Maybe it would have been wiser to explicitly exclude RPGs to from the discussion, that's why I tried to give examples instead of definitions.
Therefore let us exclude all RPGs from the discussion.