$40 is cheap for a 43 DA placement, and the usual reason is nofollow policy, small traffic, or both.
Tech audiences are the least tolerant of marketing dressed as engineering, and the editors of these sites know it. The pieces that get published, indexed and then linked to by other people are the ones with a claim, evidence and a reproducible method. Anything that reads like a feature list gets cut back to two sentences and a bio link.
Within the Technology section of the index — 53 listings, 41 median DA, 15.5k median traffic, $40 median price — this placement is within a few percent of the median on cost and about 9.7× the index median on audience. Listings in that section range from $30 at the cheap end, so the question is not whether $40 is high for a link, but whether it is high for this one.
Expect editorial standards to be enforced on the structure as well as the tone: no thin affiliate comparisons, no recycled press copy, links that go somewhere the reader needs rather than somewhere you want. Sites with 53.2k monthly visits cannot survive publishing filler, so write for their reader first and your anchor second.
The index lists this property's editorial links as followed. Availability of a followed link changes with the site's monetisation decisions, so we confirm the tag on the live URL before counting delivery.