I'm also not yet on Idena that time, there are a lot of complaints on Idena channel about wasted invitations one guy even go to the extent of selling his invitation code, so people who got the code will verify and it will not be wasted I don't think it's a good idea even if they promise that they will give back the money if they verified, why if the newbie fails the test, it's too early to monetize the code, we need more people coming in.
Those users that selling their invite via telegram is just probably joking to troll those users that keep asking for an invite code every week. Someone even asking for 20 invites in one go because of the misconception that the invite code is the only requirements to start mining
