Even during SOM we had no paid transfer options. According to a Blizzard statement there are no plans this round either for any transfers.
Edit:
While the in-game shop is available in the WoW Classic client, Blizzard doesn’t have the ability to disable it for specific servers (such as SoD realms).
There’s a disclaimer that its not available for Seasonal realms on the site and BNET app, and I recommended they add it ingame too.