While the emotes are not yet available in the game, CM Sapience announced on the forums that players have a chance to win one for free through the LotRO lottos:
All weekend long we'll be running lotteries for the brand new, unreleased, Mounted Rear Up emote. That's right, Mount Emotes are coming to the LotRO Store! Enter the lotteries this weekend and you could win it for free, before your friends can buy it. You'll have a few weeks to show it off and brag before it hits the LotRO Store.The LotRO lottery system is available on the my.lotro website.
Check back often as new lotteries will be starting randomly throughout the weekend and on Halloween!