Last week, Microsoft unveiled retail pricing for Windows 7, the successor to Vista and Microsoft's hope for a revival in operating system buzz.

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But as soon as the sheet was yanked off the price board, people started asking questions. How much for this? What will I pay for that? The questions were endless, it seemed, even though Microsoft culled Home Basic from the line-up, exiling it to the "emerging markets" category and banning it from retail.

You'd think that with just three retail editions -- Home Premium, Professional and Ultimate -- navigating price waters would be a snap. Not so.

Your questions on cost, our answers on prices follow.

What's the cheapest price for Windows 7? Unless you're buying a new PC -- more on that later -- the best bet now is to reserve your copy at Microsoft's online store or one of the retailers participating in the discount offer.

Microsoft's selling Windows 7 Home Premium Upgrade for $49.99 until July 11 in the U.S. and Canada, and Windows 7 Professional Upgrade for $99.99. Actually, "until July 11" might not be accurate, as Microsoft has made it clear with repeated references to "until supplies last" that it may cut short the deal. Since the company hasn't been straight about what that limit is, if you know you want Windows 7, get it sooner rather than later.

Most retailers have followed Microsoft on prices, but some have strayed. Sam's Club, Wal-Mart's members-only, mass-quantity chain, has the lowest prices we've seen: $44.88 for Home Premium, $94.88 for Professional. Costco, another big-box store, comes in second with prices of $47.99 and $97.99.

Should I wait? Is it possible Windows 7 will be cheaper in a month? Probably not, say analysts. Microsoft may return with another discount later -- as the Oct. 22 launch date gets within shouting distance -- but a deeper price cut this summer is very unlikely.

How can I find the best deal online? If you don't trust our scouting report (see above), or figure there's an even better deal, reach out to the participating retailers to see their upgrade prices. In the U.S., they are: Amazon.com, Best Buy, Costco, Frys, Sam's Club, Newegg, Office Depot, OfficeMax, Quill, TigerDirect and Wal-Mart. Microsoft's posted links to each retailer, as well as to its own online store, here.

I keep hearing about a free upgrade. What gives? That's the premise of what Microsoft has dubbed the "Windows Upgrade Option" (WUO) program, the newest version of what it called "Technology Guarantee" in the run-up to Vista's 2007 launch.