Buying a name with a trademark in it and reselling it often times will be considered bad faith. Now, on the other hand if you bought AppleToothbrushes dot com, if you used it to sell/promote/inform on toothbrushes, you are probably going to be ok (assuming there isn't a tm for 'apple' in relation to toothbrushes). Reselling... depends on the name really whether the tm owner will come after you... there is always a risk. IMHO not worth it (without knowing what the name is of coarse).