Occasionally you can find a parts set. Complete gun minus the receiver. I’ve seen them on Gunbroker, eBay, and a few of the other gun sales/auction websites.
Sometimes they go for silly money, but occasionally you can find a decent price on one. Seems deals are fewer and farther between these days, though.
I already had a barrel & bolt. Bought a stripped slide, to make the caliber swap even easier (don’t have to remove the bolt from the slide, just swap the whole slide). But by the time I sourced all the small parts, I’d have been much better off of I’d have just bought another complete gun.