Healing potions available

Espirit now has the Brew Potion ritual and can make Healing potions.

Instead of having one or two available to the whole party, any PC can buy as many as they like for 50gp per potion.

Espirit also has Enchant Item and can make any itel of level 5 or lower.

2 things...
Now that we can buy healing potions, Gabby is planning on swapping out her cross class feat that gives her 'healing word' for 'quickdraw', so I'd buy potions rather than count on her healing.
I was reading the DMG & I have a question: Are we supposed to be buying items from the book at 10% - 40% markup above book price? It seems like we are and that would make sense as to why create item costs equal book values... (Optionally, the DMG says it might be 10% discount to 50% premium.)

I really don't like the 4E econimic rules in the PHB/DMG. It makes no sense to me that an NPC could sell an item for less than it costs a PC to make.

A level 1 item has a market value of 360gp and it costs 360gp to make the item. How can an NPC sell the item for less than 360? Also, if a PC wants to sell a level 1 item, they only get 72gp.

I know that they wanted to avoid item crafters from getting rich, but they could have set things up much better.

...all I can say is, as an Economist by study, yeah, it really doesn't fit any Micro Economic model I've ever seen by a long shot.
...from a game balance view, yeah, they did it so that you really have to find items rather than craft them if you want an item of over your level. Even if the item is within your ability to craft, you won't be crafting items often as there's no profit in being an item crafter anymore. Perhaps that's what they were driving at, if there was any profit in crafting items, PC's would be crafters so they could make the optimal items, now they have to adventure and hope the DM puts items in the treasure that fits thier build.

That makes some sense & goes on all the time in the real world too. If I made an item that costs me 360gp to make, which I hoped to sell for 360gp + 10% to 40% markup, and it wasn't moving, instead of sit on 360gp worth of inventory that isn't earning me anything, I'd fire sell it to at least get 324gp back and not make that product except for 'on demand' in the future.
Think of the 'Clearance Rack' at the department stores. You take the loss to at least recoup something.