Microtransactions in V Rising are summarized as...
At the moment the only form of monetisation in additonal DLC. This DLC is all cosmetic only and provides no extra content. One of the DLC packs is more expensive than the base game itself.
There currently is no in-game store or season pass, but they aren't ruled out for the full release of the game. In an interview the developers had the following to say:
Ruth: Argon again and others asks how the team plans to support the game long term, financially? Will there be microtransactions, season passes, etc.?
Johan: There is no in-game shop planned for the Early Access launch, but we will release various DLC packs. More information about our first DLCs is coming very soon, something special for fans willing to give us some extra support during development. I wouldn’t rule out season passes, but it’s not on the road map for now, as we want to finetune all mechanics and focus on making V Rising as great as possible for the full release.