Roadster charges $200 for the SH847.
http://www.roadstercycle.com
I don’t know of anyone that sells the SH775, but the SH775 is used by several bike/atv/etc manufacturers.
Polaris is one that I am aware of.
Polaris part # 4012941 is the SH775. It retails for $180.
A few eBay retailers have it listed — you can confirm that they are correct per the video.
Some online dealers discount their OEM parts, so you can get it for less there.
The Roadster price for the SH847 is quite reasonable given the other stuff they include.
They may resume selling the SH775, so it might be worth checking their site one last time before ordering elsewhere.
Suzuki GS bikes have a common problem of the stators eventually failing because of the shunt voltage regulator.
A lot of GS owners use the Polaris part & are happy with the results.
Polaris was undoubtedly confused by the large number of rectifier/regulators they were selling until they found out about the reason.