I think there should be a option in the config to enable this:
http://gyazo.com/f1f148c78c73198847a65857d3eff72a
http://gyazo.com/a5516b54d64f69076f576b72f5f8c08c

Basically displaying the money you get or loose from usage of the Essentials Signs gets displayed in the middle of the screen like shown above.

Why? Because selling a ton of stuff could spam your chat so much that you wont catch much of whats going on there when buying a lot of stuff/selling a lot of stuff.

I think these messages displayed on the screen could be configurable, and editable to add color coding and rewrite what will be displayed (probs in the lang file.)

So in titles? It sucks because there isn't API for this in spigot yet :(

Yea in titles I guess it would be, oh but wouldnt it be able to use another API to do this though? (As Ive seen it be done a lot around servers)

Looks like named items and item frames. As for the action bar, like @drtshock said, there's no Spigot API interface to send them (you have to use either reflection or link against NMS, both inelegant solutions).

I was not talking about the item frames.. But yea..

Closing this since in 2020, there is still not a consistent API for doing this on all servers. Adding title bars to various parts of the plugin in general should probably be better discussed in #2391.