It looks like there's now a deal for something called PLUSBUS where if you buy a train ticket, you get a discount on bus fare in various destination cities. I'm taking the train to York, need a 7-day bus pass (which is available through PLUSBUS for £12, a £3 discount), but the only PLUSBUS I'm allowed to buy online is a one-day ticket. It looks as though I can get the discounted week-long pass at the York train station once I arrive, as long as I present my train ticket to prove eligibility.
This seems like a great deal, since I'm actually going to be there for 8 days. Has anyone else used it?