Here is an alternative cheap good Windows 98 gaming PC (because everyone has done an AMD one so far).

A Socket 8️⃣ 478 motherboard by SIS - any will do but SIS chipsets allow for PCI soundcards to work better in DOS.

Literally 8️⃣ any socket 478 Pentium 4 CPU is "good" enough for Windows 98 and fast enough (or faster) than the CPUs 8️⃣ people were using at the time (up to 1.4GHz Pentium 3) (but make sure it is compatible with your board 8️⃣ - buy the board first!). I would aim for 2GHz and up, and these are easier to find than the 8️⃣ older slower ones.

Literally any DDR1 RAM. The speed doesn't matter because any DDR1 RAM is faster than what was "good" 8️⃣ for Windows 98 (133MHz SDR RAM). Only use <512MB because that's what Windows 98 supports natively. Windows 98 games generally 8️⃣ use a max of 256MB and I would be quite happy if my Windows 98 PC had 128 to be 8️⃣ honest. You can patch Windows 98 to use more ram but the patch brings about issues of its own and 8️⃣ considering that Windows 98 and its games don't need the RAM, I wouldn't bother with it at all.

Sound cards are 8️⃣ tricky - yes you can spend lots of Yamaha PCI sound cards but a loved/hated Soundblaster Live (or Audigy1) will 8️⃣ give you basic sound in DOS and good sound in Windows games. They're dirt cheap and readily available, but you 8️⃣ might be waiting for a while for a Yamaha to crop up.