A friend of mine just scheduled me for a storytelling gig at her one year old's birthday party. My price? Two pies. I told you I was open to barter and trade.
Another friend of mine asked if I'd be willing to trade her photography services (I need some good professional shots without distracting backgrounds) for guitar lessons for her husband, but I didn't think that was a fair trade-- I've only been playing guitar for two years, and in general I am not a good teacher.* I did offer to invite the family over for dinner and show her husband a few chords. That's not teaching, that's demonstrating.
And perhaps there will be pie.
*This isn't false modesty. As an English major, I encountered some pressure to become a high school teacher. I would have been dreadful, mainly because I would have hated it.