A [Buy] sign selling 17.4 produces an invalid graphic (purple block) Acacia wood that CAN be sold back to the server for the proper amount (4).

A [Buy] sign sellin 162.0 produces a proper Acacia wood but it can NOT be sold to the server.

Can you please post the exact text displayed on the Buy sign.

[Buy]
1
17.4
p1

[Buy]
1
162.0
p1

p is my currency (potatoes) just switch for $1
Then try to "/sell hand" on both

On the same token, Cocoa Beans and Ink Sac are the same base item number (different damage value), but when you sell the Cocoa Beans it tells you that you've sold Ink Sacs :) Also, this may be economy breaking for Chocolate farms since you can't set Cocoa Bean price separately?

The issue with Acacia Logs is that the idea is actually 162 not 17:4. I'm not sure why 17:4 gives you an item name of Acacia Wood, I suspect that might be a bug on Minecraft's part.

Anyways, /sell uses the worth.yml file in the Essentials plugin folder. So you need to specify a price for item id 162.

RE: Ink Sacs, that's probably because the cocoa beans is of the same item id as ink sacs but different data value. It should not be any different economically.