To be a legit Amazon Vine reviewer you have to be invited by Amazon.
You cannot request to be a Vine Reviewer & there is no waiting list you can go on.
Any other 'company' who want you to review on Amazon are generating fake reviews (& sometimes they even fool the people reviewing for them)
If you are caught doing fake reviews you get your account closed & you are banned from being an Amazon customer.
Nobody (including reviewers) knows how they decide who gets into the program.
Some people are invited who have plenty of helpful reviews that have been voted helpful.
Other people have been invited who have zero reviews.
You do have to have spent a minimum of £50 a year of your own money on Amazon before you get invited.
They've changed most of the criteria recently, so ranks are gone & Vine is now tiered.
If you meet your performance targets, you can go to/stay in the top tier.
If you don't you can get demoted or chucked out.
Lame companies selling rubbish will try to find out who you are & hassle you/try to con you into giving them 5 star reviews.
If you do you & ever get caught, you get chucked out.
You cannot sell or give away items you have reviewed until 6 months after you have reviewed them.
Amazon can ask for them back within those 6 months (unless it's a disposable thing like food/tissues)
No matter how careful you are, some of what you get sent to review is utter rubbish you now have to store for 6 months.
You can't just cherry pick the really good stuff, you have to review some of the junk too.
The IG people have built up big enough followings that they can approach companies & sell the notion of exposure to their followers.
They spend hours contacting people to get someone to give them stuff etc..
Some companies also offer those freebies in exchange for sponsored videos to bigger channels.
You are either invited (if it's something like Vine) or you build your own 'business' & work at it like any other salesperson.
Either way it's full of hassle with people you don't leave good reviews for hating on you, other reviewers bitching about you if you get better stuff than them or they think your reviews aren't as good as theirs etc... & finding out who your real friends/family are if they discover you got stuff 'for free' & won't/can't/don't want to (because it's actually more work to keep it up week in week out than you would think) share.