Next B2G1 will probably be sometime in March-April (income tax season).
Also, to confirm, this unfortunately does NOT work on the DMC guide for anyone who is thinking about it. Sad, I wanted to do it as well :(
Also, @technicalstylez: As bj said, you get an additional 20% on the one guide (more expensive) for buying it with a game and having a PUR card. Normally, the PUR takes 10% off, but the game added on does nother 10%, plus your 50% off.