I always use momentum having previously only used shell v power. Momentum is £145.9 a litre compared to e10 at £1.38.9 so 7p difference at my local store.
you can see the price prior to pumping as once you selected payment,
it appears on the pump fuel id box.
with regards v power shell dont display price for this until selection made but again before you actually pump any fuel. I have found v power to vary from 15p to 25p premium difference.
the price of the fuel selected has to be displayed and you can always return the nozzle to holder without pumping any fuel if you not happy with the price.