If a reputable organisation held a one-off lottery, in which you stand a very slim chance of winning £5M, for a £1 stake, then (morals and poverty notwithstanding) then the default position is to enter. £1 doesn't really buy you anything much.
If, on the other hand, the stake were £52, then you'd think twice. £52 is a fairly significant sum it could buy a decent meal out for two, or the latest game with enough change for a couple of beers on the way home.
Playing every week for a year is the same as that second scenario.