well cheapest in the merchent shops are 75 mil O.O but I assume you can get them a little cheaper asking users direcly :) like the sepia ones are sold for around 2-5 mil a pair :)
I think that the one in the shops isn't a proper selling though, like in the rancher shops when they're over 2 bil... I have a pair but I was wondering what to auction them at, starting price and buy it now, thanks for the advice though :3