I use buns from the bakers, a quid for 4 and they're still warm from the oven if you go in the morning.
In the same vein, I bought some of these the other day to make some kebab type things with and they're really good! They don't fall apart like other tortillas. I had two for my dinner today with a chicken breast in each and a bit chilli sauce, salad and stuff.
respect and all but dat aint comin near my beef burger