Seems supply is drying up on G6400 Pentium Gold 2C/4T 4.0Ghz CPUs. Bought the last three that 'antonline' was offering through Newegg for $69.99 the other night. (Had five in cart, it let me add them, but when I went to check out, it said "insufficient qty.", and limited me to three. So they were apparently selling somewhat briskly.)
There was another vendor selling them for $70+ with shipping that I didn't recognize, and then the next recognizable vendor was 'beachaudio', for $99, or $90 ea. with qty. 10+.
So, either the disty price has gone up on these, or supply is getting constrained, or something is happening.
"Traditional" vendors on ebay are drying up for G6400 CPUs, Newegg themselves isn't offering them anymore (currently, at least), and supplies @ $70 or less seem to be virtually non-existant (got the last three, I think).
Considering what happened to G3900 and G3930 CPUs (mining!), raising their prices from $39 to $99 or higher, I expect that part of the demand for 10th-Gen Pentium GPUs (and celerons, which are still available @ $59 right now) is mining. The other half is, people looking to buy 500-series mobos, and drop in a Rocket Lake 8-core later on, and probably some people that just recognize a good value for a more than "good enough" desktop / browser PC, even gaming at some level.
Edit: I also noticed a rise in price in the i3-10100 (F) CPUs, especially the non-F. Before, Newegg had them for $110-115, now they're $150(!). Certainly getting more popular as an alternative to AMD's overpriced (IMHO) Zen3 CPUs.