To make a fast easy cranberry puree or sauce, put whole cranberries into water, bring to a boil, add some sugar, and keep boiling and mashing berries about 10 minutes until they are the right consistency. Adding pieces of mandarin or other orange adds a nice zing.
Cranberries are not always available in stores until before Thanksgiving; but, you can always freeze them whole. Do not unthaw before using, just wash.
Cranberry juice often contains added sugar. A few brands feature pure cranberry juice, not from concentrate. Trader Joe's is also a great source for this pure juice. Happy cranberrying!