"At no extra cost" vs "with no extra cost"
Usage:
Procedure A can thus be applied at/with no extra cost.
Which is the correct preposition here?
Solution 1:
Thanks to Dan Bron who clarified that both prepositions can be used, and taught me the correct use of the NGram Viewer.
According to that tool, "at" is by far the most used preposition:
Solution 2:
Un my opinion i think 'at no cost ' is more commonly used un British English un particular when we talk about 'financial cost. While 'with nom cost' may refer to 'saving efforts or risks'