Morph and Albino turtles are few and far between. Morphs such as albinism occur in Australian species in the Emydura complex - Murray river turtles - Emydura macquarii macquarii while Leuicism occurs in Krefft's - Emydura macquarii kreftii and I've seen albino Jardine river turtles - Emydura subglobosa bred abroad in the states. Axanthics are most common in Eastern long-necks - Chelodina longicollis.
For an albino Murray, you can expect to drop $5,000 - $6,000 but because of their rarity, unlike pythons, you'll hardly see them come up for sale.