Make a complete proposal, not just a number

When making an offer, make it complete.

A useful structure is:

• my item;
• your item;
• accessories included by both parties;
• any cash adjustment;
• who pays the adjustment;
• delivery method;
• any conditions still to be verified.

This avoids later discovering that a case was not included, the cash difference was understood differently, or one party had included shipping in the value.