How should I describe free event tickets in a recommendation without implying my opinion was bought?

The promoter's message offered two complimentary tickets to a US comedy event and asked me to share my thoughts afterward. I write occasional local-outing posts, and this was the first offer like that.

I accepted without promising praise. After the event I drafted a recommendation, including a joke I enjoyed and the slow queue for drinks. My friend suggested ending with 'Thanks for the invite.' She said announcing free tickets at the start would make everything else sound paid for.

I don't want readers to assume I bought the same evening they would be buying. I also don't want to call it a paid review when no money changed hands. The promoter hasn't asked to approve the draft.

What wording would make the arrangement clear while leaving room for my actual, mixed opinion? I haven't posted the recommendation yet.