Even if spirit sellers weren't just con artists the idea of selling spirits just seems.... Abhorrent? Immoral? The idea of binding a powerful sapient force like that and just... Selling them doesn't sit right with me at all, spirits aren't just pokemon you can trade around because you want a cool or strong one
I mean, that's certainly an aspect of it, from a spirit worker's perspective. Basically, if you want a spirit to work with, put in the time and effort to find one yourself, right? Plus the spirits offered are always suspiciously eldritch and "cool"-sounding, like Ancient Tree Bear Elemental Spirit or whatever. (Saw an actual listing for that once.)
But the larger issue, the practical issue, is that it's a SCAM. It's taking advantage of people who don't know better (and some of them probably should) and asking them to hand over Actual Money for this invisible thing that they're allegedly going to be sent via the ether or the astral realms or whatever. And there is no way to prove the seller has done this or that the promised entity has ever arrived. You just have to take someone's word for it. Sometimes there's a digital image and a description, but that's as much as you're likely to get as far as guaranteed deliverables go.
And I'm sure - I am DEAD CERTAIN - that if a customer complained like, "Hey, you said I was supposed to dream about my spirit familiar when they arrived but it never happened," the seller would be like, "Welp, you're just not spiritually open / sensitive / powerful enough, or the spirit didn't like you and left, so I guess that's that. No refunds."
I'll give the benefit of the doubt and say that there are probably practitioners out there who help people develop their spirit working skills so that they can find their own companions or reach other states of consciousness and what have you. That seems like a good and logical service to provide, because it helps people learn and further their education, provided the person in charge isn't taking advantage or charging money to spout useless buzzwords. (See: any paid service that deals heavily with the Law of Attraction.)
But charging someone on the internet Actual Money to allegedly "send" them a Vampire Blood Elf Familiar (again, an actual listing I've seen, $250 bucks and it's yours) is basically an NFT. The customer is being given a nonphysical commodity that's essentially invisible, can't be proven to exist, and has no real value, but they're being TOLD it has intrinsic value in the community where they circulate, so they have to believe that it does or risk feeling really really stupid for parting with their cash to acquire it.
So yeah, if somebody contacts you or follows you and their platform is, "I can sell you a spirit companion / daemon / familiar / etc," BLOCK THEM and do not feel bad about it. Protect your energy and your wallet.