Speculation about a Family Pack for Windows 7 began mounting last week when a couple of sites noted references to it in the licensing agreement of a recently-leaked build. Now, thanks to a couple of reliable (if careless) online retailers, the plan has been confirmed along with the expected price. As noted by ZDNet's Ed Bott, the listings are particularly convincing as they contain a Universal Product Code, the number which appears on barcodes and is unique to each product.
Retailer Expercom still has the prices live on their site at the time of writing, at $136.95 for a Windows 7 Family Pack Home Premium Upgrade, whilst University IT Computer Sales had listed it at $144.95 but has since pulled the information - a Google cache copy is available here. If the basics of the deal are indeed three Windows 7 Home Premium upgrade licenses for around $150, then there would be no reason for those who bought the single-copy $49.99 upgrade to complain.
Expercom's listings also include prices for the Windows Anytime Upgrade product line, which includes a Windows 7 Starter to Home Premium Anytime Upgrade for $81.95, Home Premium to Professional for $90.95, and Home Premium to Ultimate for $137.95.