Karma? It doesn't get more valuable after you have enough to get you past the "you didn't register your account yesterday" type automod filters. Anyone buying accounts for "huge karma" didn't fully research how Reddit works. If you have low karma in one specific sub (because you are trolling or spamming), no amount of shameless repost karma in r/funny will protect from the "you are posting too frequently" message you'll only get in the sub you are getting downvoted in.

Accounts that will likely get big offers will have a large number of followers, mod large subreddits or targeted subreddits.

Having an active account before the 2016 Russia thing is also worth something. When you want to spread misinformation or do shill marketing, it helps a lot to see any of the following when checking a user's Reddit profile:

- the user didn't register a month ago.

- the user didn't register just to talk exclusively on this subject/product.

- the user registered before Russia's IRA became active on Reddit.

- the user didn't stop exclusively participating in porn or sports subreddits just to make this comment.

- the user is writing enough quality comments that they don't feel compelled to delete most, if not all, of them.

- the user is not making contradictory claims (there is a famous example of someone claiming to be a cis woman in computers who had clearly cis male comments in several cis male oriented subreddits, one of them called something like "semen rentension". They were called out.

- the user posts in subreddits that are on good terms with the subreddit we found their suspicious comment in.

Source: I'm a Reddit moderator and work at a marketing startup.