New Feats of Strength achievements on the Patch 10.1.7 PTR indicate that players will receive 500 Tender for purchasing the 11.0 expansion. Players who purchase the Heroic and Epic versions will receive bonus Tender.
Warning: This has not been confirmed by Blizzard and is speculation based on datamining.
In the latest Patch 10.1.7 PTR, 3 new Feats of Strength achievements were added with some very interesting names:
This seems to indicate that players will receive Trader's Tender for purchasing the 11.0 expansion, whenever that is announced. WoW expansions usually come in 3 versions: Base, Heroic and Epic, with the cost and goodies increasing with each version.
From this, we can see the following amounts of Trader's Tender datamined for each version:
Will this influence which version of 11.0 you purchase?