They're really commanding a premium now. I have one in 416 Rem Mag and they're going for almost $2,000 on GB with the 375 H&H models going for even more than that. I paid just over $1,200 for it when I bought it so they're definitely overpriced now.
Unfortunately with CZ now out of the entry level safari rifle game that pretty much leaves Winchester as the only option so I imagine their safari rifles are going to be hard to get in general now. To add to that I don't think Winchester makes many of them to begin with, and they were already in somewhat high demand prior to all the craziness as they were, out of the box, better rifles than the CZ 550 magnums for only a couple hundred more. They'd come out in batches and usually sell out pretty quick.
Your best bet is to sign up for notifications on gun.deals for the 375 model and you should get notified once one is in stock somewhere. Generally that'll be the cheapest route. If you go on Gunbroker looking for one you'll overpay since none are in stock with any of the major online dealers and demand is even higher for them due to CZ dropping out of the safari rifles game. Right now it's best to just wait for one to come in stock on the regular dealer sites for just around or under MSRP.