I recently tried my hand at flipping the Librams for leg and head enchants to some pretty good success. Even if these enchants are outclassed by ZG enchants for some classes they are still going to remain the best choice in certain situations, and will fill important wholes as players get upgrades in phase 5.
Librams have variable supply and demand. They are a prime candidate for flipping as they cannot be reliably target-farmed. As such it will be very hard for someone to undercut you. Demand varies by when a player with gold gets an upgrade they want to splurge an enchant for. Personally I would only focus on the 4 most expensive ones: Constitution for +100 HP, Voracity for +8 Mainstat, Resilience for +20 FR and Focus for +8 Spell damage. The rest are too cheap to be worth the hassle.
We will be using the same basic approach I use to flipping BoEs and materials for librams. We’ll be buying them at less than 80% dbmarket and reposting at the full market value or higher. I don’t know how many would be too many. Due to the fact that they are unique you will have to store them on the AH.
I would personally not be afraid of going up to about 5 of each, but it depends on your risk appetite and gold totals. Constitution is probably the safest one as it will remain the best choice in PvP for many classes. FR will probably not retain too much value and spell damage and mainstat are both outclassed by ZG enchants for the classes that can use those.
Run a scan and shop
I included all the librams in the group, as prices may change. You simply select the group and run a shopping scan. Buy any that show up with a price below 100% (assuming you can afford/risk that amount of gold). In the screenshot below you see the current AH on my realm, where all of the librams are selling for more than their market value.
As such I would not buy any of these librams. Keep in mind that the percentage is the percentage of the maximum shopping price (80% of market value) and not the percentage of the actual market value.
Then you go straight back to the AH and repost them. Since they do not have a vendor price the deposit cost is non-existant, so we can just post all of them without fear of losing out due to deposit costs. Ass such we will post up to 5 of each Libram. Players will typically buy one, but they may buy 2, and considering the non-existant cost of deposits there is no reason to avoid posting two at the time.