Hello Pieter. The price of ship fuels are subject to fast changes, and they also vary from port to port. You can get a good idea about the prices you are after on Bunkerworld's 'Fuel Prices' pages. For you I guess Rotterdam would be most useful:
The MGO price you can see on this page will typically be a 0.1% S distillate fuel.
The MDO is a distillate fuel with allowable S content up to 1.5%, but I'm not sure what its typical sulphur content would be.
The LS380 and LS180 prices are for HFO (380 centistoke & 180 centistoke respectively) with max 1.5% sulphur.
HFO with 1% sulphur is also available from fuel oil traders in Rotterdam, but would currently normally be blended up to 1.5% S before being sold to ship.
HFO with 0.5% would be a very rare commodity and so it seems little point in speculating about its price.