I take it you are talking about Adobe CS5 Browserlab. there is an alternative:
Microsoft's Virtual PC or VMWare Workstation (or was it player? I heard one of those VMWare products did the job - comes with XP maybe?). you will probably have to slice up your hard disk into some FAT32 partitions to do this, one for each VM/IE version.
you would also need a legal retail version of the OS in question (
3 of IBM PcDOS2000+windows 3.1 [ie3,4,5],
3 of Windows 98 or me or nt4 [ie5,5.5,6], or 3 windows 2000 [ie5,5.5,6] or xp [ie6,7,8], and windows 7 [ie9beta]
I suggest you use an extended partition and stuff all these in logical partitions.
and the answer is NO. it is very costly. OS's are roughly $99-300 each, and vmware workstation also costs a chunk of change (but I hear it's worth it).
make a list of what OS's you can get legally (not OEM - beware of vendors who say full retail but it's really OEM so they can get it off their shelves).