Can a buyer's agent legally give you money back in BC?

Short answer: yes. A BC brokerage can share part of its commission with its own client. What the rules care about is that it is done openly and in writing.
Who actually pays you
The rebate comes from the brokerage, not from the agent personally. In BC, commission is paid to brokerages, which then pay their licensees. So the brokerage has to approve the rebate and pay it out of its share.
Disclosure
Licensees must disclose material information to their clients and must not mislead the other side. A large promise to the buyer that the seller never hears about has landed licensees in discipline proceedings. A clean rebate is written into the agreement between you and the brokerage, and your agent makes sure it is disclosed appropriately in the contract.
Why "in writing" matters to you
A verbal promise disappears the moment there is a disagreement. A written clause tells you exactly what you are owed, as a share of what the brokerage receives, and when. If an agent will not put it in writing, assume it will not be paid.
What can change the number
- A listing that offers less than the usual 3.22% and 1.15% to the buyer's side.
- A presale developer that pays a flat fee instead of a percentage.
- A deal where you were not registered with your agent at the first presale visit, so the developer pays nothing.
More detail in our guide to BC rebate rules.