I buy my fresh yeast from the larger branches of Sainsburys. They sell a 750g block for 99p. I used to buy smaller amounts, but was told by the assistant on the bakery counter that it would work out cheaper to buy the whole block. I don't always use it all, but at that price I'm not throwing much away. ;D
If I can't get fresh yeast I would use the easyblend type, which you mix in with the flour/dry ingredients, and then add the liquids.
I would never bother with the dried granules. If you have to reconstitute it, it can't be very good.
valmarg