Each Red Wings Season ticket holder is allowed to buy two tickets to the Winter Classic per season ticket. To do that, you also have to buy 1 GLI ticket per Winter Classic ticket.
If they screw over Leafs fans the same way, there won't be many GLI tickets available through the box office, but a ton available online.
I will be shocked if tickets aren't available for the GLI on StubHub for under 10.00 each. As stated above, the GLI tickets are part of Winter Classic tickets and most people will be looking to get back anything for them.
Should be around 10, just depends on the number of Wings/Leafs fans they can rope in.