Manorstone are a good and reliable supplier of granite setts.
Im not sure of the current price of granite setts, but certainly they were anything from €50 upwards per square metre ex vat.
Granite is different to paving in that it must be grouted after installing and is time consuming to lay.
Overall natural stone is about 5-6 times the cost of paving to lay. Note there are very nice alternatives to natural stone in paving eith granite effect finishes.