There's a 99p shop in Halifax, and I guess elsewhere, that has onion sets, shallots, good selection of potatoes, flower and veg seed and fruit bushes. I always thought these places just sold tat until I came to these forums. Poundland btw are selling cheap fleece as well as all of the above (e.g. 10m x 1m).
For anyone looking for this in Halifax, turn left out of the Tesco metro and it's about 50yds walk