Another way to put it is that they would sell you 150 backlinks.
The average monthly cost is about $500 - $3000 depending upon what services is within the SEO plans. SEO experts are those that that optimize your webpages. https://forum.mma.su/redirect-to/?redirect=https%3A%2F%2Fsupervision.NFE.Go.th%2Fchak_rat%2Findex.php%3Fname%3Dwebboard%26file%3Dread%26id%3D147958