What are the blue wings from?
They are from a festival called Dragon Bash. The wings are a earned through achievements or specific currency specific to Dragon Bash.
If you really want some could by the holographic dragon wings off the tp
There are two types. The Shatterer type is account bound and earned through an achievement. The Holographic type was a drop during that time and can be bought.
Sadly you missed the event, they are still sold on the tp no clue what the prices are.
If you want to check the price, you can look at this site: http://www.gw2spidy.com/item/43346