sushi grade fish is in reality a waste of money and time, if you want to make sushi at home, do things like this
tuna. just look for fresh cuts of tuna at seafood markets they will run you usually $15 a lbs take them home and lightly sear them on all sides, then use them for a roll
same for scallops, then they can be used in a spicey scallop roll or spicey scallep sushi.
doing this you basicly get the same sushi quality you would ecspect but dont have to worry about shitting for 5 days ccause you have a tape worm =)