Rosetta Stone Chinese (Mandarin) Level 1-5 Set shipped for $362.52 by Amazon.com
BUT, get a further $50 off if you're an "Amazon Mom" member by applying the promo code available on the Voucher. That drops the final price down to $312.90.
In reference to an earlier blog post made on buckscoop, you can actually become an Amazon Mom member without paying anything! See here:
By comparison, Angus & Robertson are offering the same set for $549 and Bookworld.com.au for $494.10.