50% Het Albino occurs when one parent is a Het Albino, as all offspring will have a 50% chance of acquiring the albino gene.
66% Het Albino occurs when both parents are Het Albino, as there are four possible outcomes of this breeding, 1)Albino 2) Het Albino 3) Het Albino 4) Normal. Due to the fact that the two chances of a het albino and the one chance at a normal all look the same (they are normal in appearance) you have a 66% chance (two chances out of three) of the normal looking baby having the albino gene.
100% Het Albino occurs when one parent is a visual albino(white and yellow in appearance) as this animal has two copies of the albino gene it cannot pass a normal gene, so all of its offspring will receive a copy of the albino gene from this parent.
That information is true for all recessive morphs, but you should make sure to educate yourself because some morphs behave differently (dominant and co-dominant) and do not have a het form. It is always best to fully understand something before spending money on it.