Indexing is the first filter
A placement that is never retrieved cannot influence anything. Before looking at price or reach, check whether recent articles from that outlet are retrievable at all: search a distinctive sentence from a piece published a month ago and see whether the page comes back. Outlets that fail this are not cheap, they are zero.
Metrics that mislead
Domain scores are computed from link graphs and say little about whether an AI answer will cite the page. A high score on an outlet that publishes two hundred syndicated releases a day is a property of the domain, not of your article. Weight the outlet's editorial selectivity above its score.
What to check before buying
Whether the piece is marked as sponsored, and whether that changes retrievability. Whether it stays up - some packages quietly remove articles after a period, which turns a citation into a dead link. Whether the outlet allows the specifics you need: an outlet that strips numbers and product names leaves you with a piece that corroborates nothing.
What a placement can and cannot do
It can provide an independent page that states a specific thing about you, which is exactly what corroboration needs. It cannot make a model recommend you on its own, and a single placement rarely moves a measured figure. Placements work as a set, against questions chosen in advance, with a recheck to show whether the set did anything.
Record what you bought
Outlet, date, URL, price, and which question the piece was meant to support. Without that record the recheck cannot attribute a change to anything, and the next budget conversation has no basis.