I posted this ticket on dev.bukkit.org but thought I'd post here too since its a bad exploit. I know it's not a fully supported version, but someone else posted it too:

Ticket 220 (and 219)

1. What server software, and what version of the server software are you running?
   Spigot build 1487
2. What version of HyperConomy are you using? (If using a development build, please provide the build number.)
   Dev build 408
3. What is the issue?
   Can make infinite money selling lower enchant than exists on item
4. With as much detail as possible, what exactly are the steps or actions to create the issue? If you're able to provide steps to create the issue on a fresh install of HyperConomy, that is even better.
   a. hold sword with looting3 enchant
   b. /sell looting2
   c. received $, but looting3 still exists on sword
   d. repeat /sell looting2 over and over to get infinite money
5. Do you have any errors in HyperConomy's errors.log file? This file will be located in the HyperConomy folder if you have any errors.
   No errors

Fixed in build 411 Thanks so much! :)