|It's actually nothing like this. I just wanted to add a picture.|
Thursday, December 24, 2015
Treasure: Bag Of Holding
To start with, it begins with Snatcher and Recall. We then need to decide on a reasonable weight limit. For now we will say 50 lbs. The One Dimension Only limitation is taken from the post credited below, and means we can't just recall all belongings if it doesn't somehow fit into the bag. So we have:
Bag of Holding (+80%): Snatcher (Recall -25%; Costs Less Fatigue 2 +40%; One Dimension only -35%; Cosmic, No Die Roll Required +100%) 
So that is expensive, but oh well, let's convert this to an item using Metatronic Generators and Sorcery.
Starting with Metatronic Generators, I think the appropriate size modifier for a bag could be about SM-4, and after looking over the modifiers in Sorcery, I think a smallish bag would have a -60% modifier.
Bag of Holding: Metatronic (+20%): Snatcher (Recall -25%; Costs Less Fatigue 2 +40%; One Dimension only -35%; Cosmic, No Die Roll Required +100%; Gadget Limitations, -60%) 
That -60% is equivalent to being able to be stolen and requiring a quick contest of ST to grab it from you in use. This bag of holding costs $24,000 at TL3 and requires an appropriate esoteric skill to access the insides. Perhaps Thaumatology if magical in origin, or Engineering(Gadgets) if created by a crazy inventor. Finding the item takes 10 seconds.
First off we need to take off 1 level of Costs Less Fatique, No Die Roll Required, and apply Mana Sensitive. We need to add on Takes Less Time as well to make it last 1 turn or less.
Bag of Holding: Sorcerous (+30%): Snatcher (Recall -25%; Costs Less Fatigue 1 +20%; One Dimension only -35%; Mana Sensitive -10%; Reduced Time 4 +80%) 
This bag requires 1 FP and an IQ roll to retrieve items in 1 second. The multiplier for a bag is 0.4, which gives 42 Enchantment Points. The raw materials, canvas for the bag needs to cost at least $700. So it is a pretty fancy looking bag. Labor costs $13,440.00 for a mage to create it. This item is likely to cost $28,280.00 at retail.
If you *need* to store/retrieve items bigger than 50 lbs, the metatronic version's price can be increased by $6,000 for each doubling.The Sorcery version can be doubled for $7,680, but each doubling also increases EP by 12 which increases the cost in raw materials, time to produce, and point investment. The Sorcery version is easier and faster to use, but the Metatronic version is cheaper to build.
This is heavily based on this post.