Rowlawn who have distributors country wide, deliver bulk bags (like you get builders sand in) of fruit and veg compost which I would really recommend. Lovely mixture of topsoil and blended sterile composted material/manure. Really holds onto moisture well. Bags hold 1 cubic metre, details on their website. Cost delivered to my part of world is £124, cheaper as you get more delivered.
Bulk bags are usually 2 cu/m, because potting machines used by growers are designed to take them. You sure there 1 cu/m ? Usually the only other version is 3 cu/m compressed bale, same physical size, but that designed to go on a bale ripper to unpack it. Ive never seen a 1 cu/m bag.
to work out if its cheap you need to reduce it to the same bag size for comparison - 1000L = 14.28 x 70L bags, which is £8.68 a bag, which is seriously expensive. If they are 2 cu/m bags, which i suspect they may well be thats £4.34 per 70L. Its still expensive, so you need to know exactly whats in it to see if its worth it. The first place mentioned, selling at £3.90 for 70L, works out at £55 a cube.
For reference, the price growers pay for compost by the 2 cu/m bag is between £30 and £70 cu/m and for £70 a cu/m you would expect to get CRF's, wetter and other enhancers, and top quality peat in it..
Buying in bulk can get wiped out by the delivery costs on partial loads. Take bark - i know several places you can buy landscaping bark in bulk, and a full 80 cu/m load works out at about £30-£50 cu/m. If you tried to buy say 15 cu/m, you would end up paying £120+ a cube which is entirely uneconomic, and cheaper to buy it in bags by the pallet. This is because the lorry will cost you £400-£900 to hire, irrespective of its load size.
It might be cheaper to collect a bag on a trailer or flatback lorry obtained yourself, they will forklift it on but you will have to handball it off at the other end. That could make a significant difference to the cost.
**Edit**
I just had a look at there site. What they are selling you is not compost, its topsoil blended with possibly green waste - it states its peat free. Thats why it costs more.