Is there some secret to getting a Pi at MSRP or is it just another victim of the semiconductor shortage? I can't find a Pi Zero W for under $20 or a Pi 4 for under $50.
Try also sparkfun.com. Sparkfun and Adafruit both have a "notify me when back in stock" feature where they send you an email if and when the item becomes available. That works pretty well. If something is in short supply it tends to sell out fairly quickly (like within days or hours), but it's usually not so intense as to sell out within seconds. So if you check for the item as soon as you receive the email, you can usually get one.