Some right, a hair of down usually. the theories on this abound, and none is right or wrong.

if you want to be safe, shoot for 2-3 degrees of right and .5 of down. the smaller the plane, the less it needs generally speaking, so long as the tail moment isn't too short in relation to everything else. Then you will need more. this has more to do with the prop than it does with the plane itself if this is not a short coupled plane. A high diameter low pitch prop will need slightly more than a smaller higher pitch prop turning faster.

Keep in mind this is just generally speaking, you can get away with none at all if your plane is properly designed, trimmed and set up otherwise, and you may still need a little mixing. if you start with a little default right thrust, say 2 degrees, that should be a good starting point on a cheapie plane. Flight trim from there....

-Mike