He's full of crap. Any of them that are obviously in good condition go for thousands of dollars with T1 processors. Some of those without HD's, used, and in unknown condition go for several hundred. Not apples to apples, though, as no business will depend on such unknowns for mission-critical stuff that SPARC is best used for.
Interesting enough, even the AlphaServers still sell for good money on eBay. Certainly they were great servers in their day but performance is way behind. While faster Itaniums from SGI you can get for $100-200. Old hardware market isn't linear or predictable. Personally, though, I think those AlphaServers are still worth if if one understands OpenVMS clusters or PALcode. ;)