There was a pretty big website I used to buy stuff like Linksys hubs and networking cards from but I don't recall the name.

Made quite a few purchases from egghead.com back in the day.

http://web.archive.org/web/19970619020856/htt … ww.egghead.com/

As already mentioned, online PC parts stores did exist, although they were not yet the large go-to websites that they are now. My first self-built system didn't come until 2002, so I was a little late to the game. I primarily used PriceWatch to find the lowest possible prices, so I ended up ordering primarily from smaller, lesser-known online stores that sold computer parts. The only one I specifically recall the name of was one called GoogleGear (No relation to Google the search engine), but I don't know if they existed in the 90s or not.

As for strictly back in the 90s, I do remember Tiger Direct existing then, but I never ordered anything from them. We had a local computer store that I recall buying some parts from, I imagine it would have been possible to get everything needed to build your own system from them. I also had a subscription to PC Magazine during the late 90s, and I know there were TONS of advertisements for various companies big and small that sold mail-order computer parts. I don't remember the name of it, but I also remember a separate mail-order computer system/component company that printed catalogs with raccoons on the cover.

I think online archives of magazines are still your best bet. This is what I used as a price guide and would get the base build of a local PC store as they could do that cheaper and then upgrade Ram, graphics, Networking cheaper our selves for from computer fairs.
Those Add's in the back of magazines that are nothing but big price lists often sold OEM hardware, as did the fairs.

Not that it helps your pricing but if you were into computers you would usually know at someone in the business who would sell you hardware at cost price or at least mates rates, another source of OEM hardware.

I ordered a custom-built PC from Micro Express back in 1999. I still have the motherboard, RAM, CPU, and case to this day, and they still work. Darn shame I didn't keep that AWE64 Gold card around - that thing was a beast and worth a lot of money still today. I thought Micro Express got bought out a long time ago, but apparently they're still around. They dropped their steam locomotive logo, though. I still have that sticker on my old case to this day.