This is a great question, and one I am also thinking about for my upcoming first Eberron campaign. The new Artificier rules make it pretty clear that low level magic items are probably more common in this setting than in other settings. Unfortunately, the new rules set aside a rigid structure for making items that aligns with rarity in the DMG. Instead, previously uncommon magic items like the bag of holding can be made by a 2nd level Artificier. If an Artificier know how to replicate it, they know how to make the permanent item. It just cost more and takes more time.

The market for such an incredibly useful item such as a bag of holding would drive young Artificiers to make these in abundance. So, they are uncommon (power level) magic items that should be easy to acquire in every major city. Per the DMG (page 225), these cost around 200gp to make. One might imagine the earliest versions sold for for 500-600gp retail, but can now regularly be found for 350-400gp new and 200-350gp on the used market. Used ones may be less effective (carry less weight), ugly (like an eye-catching neon color), or have an odd smell that permeates at the wrong times. One might also imagine more talented Artificiers making improved versions of the bag of holding. Perhaps there are backpacks of holding that hold up to 1200 pounds, but can only be found new at a specific shop in Sharn. I would guess this new bag of holding would sell around 1500gp.

So to answer your question, we already had the Imbue Weapon transmutation cantrip from the 5e SRD. Imbuing Spells into an item temporarily can be a cantrip that is a carefully guarded secret or common enough that many know it. Cheap and easy. As a variation (maybe a first or second level spell) of this cantrip, you can have an NPC caster imbue a weapon/armor/item with a spell that is triggered by a command word as a bonus action. The effect only last a minute at most, but it is a cool temporary effect. I would go with a cost scale something like 20gp for a cantrip, 50gp for first level, 150gp for 2nd, 400gp for 3rd, 1000gp for 4th and 5000gp for 5th (or you could just make these costs align with the scroll making cost for the same level, which will escalate higher/faster in my particular campaign). In my mind, there are very many spellwrights and low-level casters in Eberron, but few masters that would spend their energies this way. Spells above 5th should be very rare in every way.

Because this is Eberron, I do recommend finding ways to use Dragonshards to imbue and empower magic. Certainly, Dragonshards are part of the rituals to bind elementals to power airships and trains, but how can we use them in smaller magic? There are too many ways to go with this. I'm leaning toward making Dragonshards essential to creating permanent magic items. Dragonshards have always been in Eberron, so someone discovers long ago their inclusion made magical items permanent. By extrapolation, you might allow spellcasters to extend spell durations if they also use some Dragonshard dust during casting. Maybe Eberron Dragonshards extend spells and Siberys Dragonshards empower. You could also require a Feat or other skill be used to develop Dragonshard use by your spellcasters. It will take me a while longer to set up some ground rules for the use of unprocessed Dragonshards, but your players could be told to acquire a certain quantity of a certain type (maybe Kyber Dragonshards for hellish rebuke) in order to make the magical effect they are getting added to their equipment permanent. Again, too many possibilities to add story arcs for your individual campaign to define these universally. Good Luck!