Where do you buy your tubes???? It seems like yesterday I had 8 tubes and now I am down to 1 lonely tube. Buying them at the local bike shop can bring an OUCH to my wallet and really need to buy them in bulk since it seems they disappear so quickly.
I buy 'em for cheap, usually online at performance or similar. They're $3.99 now, but they get cheaper and I always wait for a 20%-off coupon to stock up.
Roger that, or pay the big bucks once and get Slime tubes (recommended for training only) and don't have flats (unless you really can't hop over the holes or run your tires at too low of a pressure).