The power adapter, 16v, is available on eBay... China version is $9.99.
Genuine Canon sells in a variety of prices from $18.95 including free shipping, up to $27.99. Delivery in 5 days from USA sellers to USA addresses... 11 days from China.
Our clients are always losing them, or breaking the cable. We have obtained hundreds from eBay over the years. Never yet had a bad one.