I happen to be on a few teams and many of them have threads where you can promote your sale or coupon code. I do find the best way to promote is outside etsy, using twitter, google+ and facebook. You can also use apps like Betsi for free tagging and price reduction.
One site I use is etsy on sale which will auto tag & slash prices only you have to use credits, everyone who uses it can get a referral code to issue to people for $10 in free credits more than enough to run a sale, add a tag and tag removal when it's over. You can send me a convo if you'd like my referral code for the discount.
Also etsycouponcode.com is a place where you post and manage your discount codes and they promote for free as well.
Hope this helps and good luck with sales.
