There is 25% off on GMG for Europe with VIP5 coupon code if someone is interested. It's a good deal for Deluxe Edition especially since you can find better prices for basic version elsewhere I guess.
This did it for me: getting the Deluxe Edition for £53 is pretty good. I was on the fence because I didn't want to fork out for the DLC without knowing what it was, having little interest in maps and scenarios. But having now paid the equivalent of £13 for all four, even if two are complete rubbish I think I'm probably still saving on buying them à la carte Day 1, which I almost certainly will for new Civs and Leaders.