As an example, the new store doesn't replace in-game venders whatsoever. However, depending on the in-game store you're using there will be a corresponding banner at the bottom. Looking at some potions? The banner will remind you they can also be found in the DDO Store, just click the banner and whoosh, off you go! The purchasing process will feel instantly familiar to anyone who's shopped on a decent online store, expect you're dealing in Turbine points and there's no shipping and handling. And although I was told the pricing for items is still in flux (so ignore what you're seeing in our screens) most of what I saw didn't induce sticker shock. In fact, a lot of it seemed pretty reasonable.
So we know what free users will be doing with the DDO Store (buying chunks of content at their discretion) but what about regular subscribers who get all the content and have a monthly allowance of Turbine points to spend? Most likely, they'll be purchasing experience potions and/or items during dungeon crawls, because what you buy goes directly into your item bag. More on this topic later.
Let's say you're trying to solo an instance as a Cleric, but having a hard time of it. You simply buy a hireling contract and open it from your inventory to move things along. Still having trouble, because you thought you'd want a challenge, but it's harder than you expected? Gold Seal contracts allow a player to have more than one hiring out at a time -- you can even fill an entire party this way.
Browsing the various sections of the store my eye kept coming back to the "Level & Stat Boost" section, so I asked what it as all about. As it turns out, these actually aren't levels you can buy in lieu of actually playing the game. Rather, these are leveling sigils that unlock a set of levels (I believe it's four at a time) and really are of no importance to subscribing players, although they can also be found while questing. My guess is that they're scattered amongst free and purchased instanced and wilderness content, but the ones offered in quest rewards can be overlooked for a shiny new piece of equipment. In case a free account player picks one of these over a leveling sigil, they can always find them in the store -- although at what price I couldn't say, because I had none to purchase.
There's a lot in place to keep players coming back to the DDO Store. VIP players not only get a monthly allowance, but for every 100 favor points earned they get another boost to their Turbine points. Additionally, VIP players can purchase guest passes for content that a free account doesn't have. This way, if there's content you'd like to play, but your free account buddies don't want to pay for it, you can bring them along and they pay nothing extra. I suppose it just depends on how much you want to play that content with other players and not hirelings. Hopefully your friends are thankful for their free content