So, I am at a point in my application whre I need to start caching results from my database. For that, I know I can use unstable_cache, that by what I understand, uses under the hood some abstracted away service Vercel provides to store my data in a cache outside my serverless deployment. This means that reading and writing to the cache has a certain pricing to it etc.

Also, I could use something like Upstash Redis to do my caching there.

Which should I prefer using? Is there a reason I should use both? Which one should be less expensive for scaling to multiple users?