Content is sold by the piece because that is the easiest thing to count, and the price per piece varies enormously for what looks like the same deliverable. Almost all of the difference is the writer: their subject knowledge, whether they interview your specialists, and whether they research or summarise what already ranks.
The writer is the price
A generalist working from other websites produces a competent summary. A subject literate writer interviewing your specialists produces something competitors cannot copy. The second costs several times more per piece and usually less per result, because on a competitive subject the first rarely earns anything at all.
What tiers usually vary
Number of pieces, word count, whether research or interviews are included, revision rounds, whether images are produced, and whether publishing is handled. Word count is the easiest thing to scale and the least related to whether the content works, which is why it separates tiers so often.
What is usually excluded
Original research, images and design, interviews with your team, internal linking across the wider site, distribution, and updating what was published last year. The last is frequently the highest returning content work available and almost never appears in a package, because maintenance is harder to sell than production.
Comparing two quotes
Ask who writes, whether they interview, how subjects are chosen, and what happens to a piece a year later. Those four answers make packages comparable and usually reveal that the cheaper one is a different product rather than a better price.
Questions people ask about content marketing pricing packages
How much should an article cost?
Quotes vary too widely to state responsibly. The useful comparison is who writes it, whether they interview your specialists and how subjects are chosen.
Is more content better?
No. Fewer pieces answering what buyers actually search will outperform a larger volume written to fill a calendar, which also dilutes the site.
Should a package include updates?
It should, and it usually does not. On an established site, updating and consolidating existing pages often returns more than new publication.