How to chat in "all/allies"

Dumb question, yes. But I've been trying to ask a question through "all" chat, but I don't know how to do it.... Since I'm already posting here, is anyone able to answer my question:

How much are fresh 6* units (from standard pullable packs)?

How much can a maxed 4* unit go for?

All means a message was sent by that person to all of their allies. this is done Via the message box in your ally tab.

Fresh 6* unit prices are dependent on what unit it is.

Max 4*'s should normally go for 2-3 TE however finding buyers for anything below 6* currently is a pain. Also trade lock is active atm due to guild event.

thank you for responding