If you need support from Yola please contact us via firstname.lastname@example.org or make use of our live chat service! We are working on a new approach to community-based support and during this transition period we are not adding any new threads to this forum. Many thanks to everyone who has participated over the years and we look forward to unveiling a new peer-to-peer support system soon!
The Online Store as you say doesn't have an auction facility. It has been suggested but it hasn't been supported by other users voting up the idea.
You can export your products into a CSV file then with some manipulation into ebay's Turbo Lister and upload them to an ebay store which would then allow you an alternate channel to be enabled. There have been quite a few Ecwid store owners who have done this.