"Post-Life" spelled items are spelled items that were made between November 11th 2014 and December 17th 2015, they were made using a glitch where you could trade the spells without them expiring.

If the account didn't launch TF2, spells would remain in your inventory, and the person receiving the items in a trade needed to be in "offline mode" on Steam and then "sort" his inventory after accepting the trade, thus making the spells appear without them expiring in your inventory, and you could still use them on items, before the "Tough Break" update that made the spells Un-Tradeable, making the glitch impossible, thus stopping the making of new "Post-Life" items.

"Post-Life" spelled items prices may be a lot more expensive than the regular spelled items due to rarity.