Seller is Kai Seng Computer Solutions Pty Ltd, which runs several seller name on eBay: e.g. FutuOnline, ShallotHead etc. It seems like it is undercutting most of Computer Alliance's intel CPU listing prices by $1.
I didn't bother listing the other i5 -K SKUs, as the Ryzen 3600 is currently available at ~$260 (as posted by doweyy), considering the performance similarity and overall platform costs, the Ryzen 3600+AM4 would be my personal pick. But if you want the i5 -K SKUs, just give eBay a search.
So the CPU choices here are either you want something more in the line of better performing "budget" build (forget the Z490), or if you need something heavily threaded for heavy workload. Anywhere in between, the Ryzen 3600 still has the best value.
Intel Core i5-10400F (6 Cores, 12 Threads, no iGPU, comes with intel stock fan cooler in box): https://www.ebay.com.au/itm/254699086588
Intel Core i5-10400 (6 Cores, 12 Threads, has iGPU, comes with intel stock fan cooler in box): https://www.ebay.com.au/itm/264744664521
May be suitable for those needing/preferring an iGPU to transition between builds/periods of no dGPU, or those don't require a dGPU.
Very limited quantities listed for the following i7 SKUs. The prices are good for those needing hardware for 8C/16T workloads:
Intel Core i7-10700KF (8 Cores, 16 Threads, no iGPU, overclockable with Z series MB, no cooler): https://www.ebay.com.au/itm/254317957884
Intel Core i7-10700KA (8 Cores, 16 Threads, has iGPU, overclockable with Z series MB, no cooler): https://www.ebay.com.au/itm/274497688282