uhm, looking at your list i'd say Aldis!!!!
do you really not know how money works??
guess it all comes dowen to the size of the respective bags being sold there.
i'd always jsut buy one of the bulk bags for £25 - that should last for most of your needs, and takes 2 mins to sieve it if you need fine compost for seeds.
then again - it all comes down to space i guess.