I spend roughly £40 a month on fish food, some things like bloodworm in a 1/2 kilo slab and kilo bags of mussels cockles and sprats i buy monthly, other stuff like whitebait, prawns and live shrimp i buy weekly so the weekly ammount varies as to what needs replacing when.
Why are you buying little packs of bloodworm? I presume you use Ashford aquatics in Vermulens garden center sometimes? Just ask behind the counter for the 1/2 kilo or 1 kilo packs of bloodworm, 1/2 a kilo is £6.50 i think and a kilo is about £12, i preffer the 1/2 kilo packs as they can be snapped easily where as the kilo ones need beating with a hammer and that can get messy.