As you know Walkera discontinued the Devo 6S quite a while ago. They were a HOT ticket item for Deviation fans long after Walkera stopped building them, (driving prices up). But interest in the 6S seems to have faded now that we have more choices in the market for a multi protocol tx, in a small form factor.
You could do an eBay search of Completed Listings or Sold Listing to see what and buyer and seller were willing to trade one for. But lately, even that approach is a hit-or-miss strategy, since they simply don't come up for sale much anymore.
I bought my 6S (new condition), on eBay back in May 2017 and paid $225 USD. But since then, I've seen used ones it go for as little as $150. Truthfully, I reach for my modified 7E way more often than my 6S, primarily because I can read the B&W display in sunlight. Like you, I'm considering selling my 6S, but as of today, I'm not actively listing it for sale.
