Wow good luck with that, where have you seen a DotA 2 invite seen sold that high? I've given all mine for free since everyone has tons of them already. The invites you have are not the early access ones that Valve sells. Check ebay for real prices on DotA2 invites and you'll see they are really only few euros...

If you have anything good to trade I could trade CS GO for instance, but not for DotA 2 invites that are worth nothing.

EDIT: This post is partly for those poor souls who could believe they are getting an invite worth 27 euros, as in, you scamming them for something worth a lot more than your invites.