Where can my friend buy a Windows 98 CD?

[Gukumatz]

From the FAQ:

@C_K_Dexter_Haven

File-sharing software (used to distribute files over a peer-to-peer file-sharing network) still has nebulous legal status in the United States of America (the location of the parent company behind the Straight Dope Message Board), and is often used for copyright violations.

At the SDMB we take copyright violations seriously and this is an issue close to the heart for the owners of the SDMB (the Chicago Reader). For this reason, we ask our posters to refrain from discussions on how to use file-sharing software at the SDMB.

Debates on the legality of this practice are allowed, but do not ask questions of the type “How do I get this peer-to-peer sharing software to work?” or “Can someone help me find a copy of (song or movie clip) using peer-to-peer sharing software?”

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We still recommend anyone who participates in copyright infringement or piracy to be careful about discussing it on the boards, as we will not remove it later. Anything posted here that does not violate our rules, stays here.

On to the OP:
Sunspace, Microsoft no longer distributes Windows 98 as that was one of the terms in Sun Microsystems’ lawsuit settlement back in 2001. (Sun Vs. Microsoft, 1997-2001) Those systems were phased out over a few years; in December 2003, Microsoft officially retired Windows 98 and cut all distribution through any channels. So your friend is basically restricted to the second-hand market, finding someone running a VM they could borrow access to or the Windows 7 W98 compatibility mode.