So we are looking at around July as being the last most stable updated builds to be made & the ones to keep before you can afford to buy it.
Prices pending...

but I'm sure they will be more than we want to pay!
This is a very short time away so hang on to the latest leaked builds as they will be the closest to the RTM version.
"Windows 7 development should finish up in July, at which time it will be released to manufacturing. The October 22 date will be a full retail rollout, although pricing has yet to be announced."