As for the first line, it uses the figure of speech of the anaphora, which as an identity by similarity (better, here, identity by semantic and phonetic identity: Leggero ... leggero, ie. Light ... light), so it is persuading. Moreover, it relates to an opposition (normal and reduced price), which, as repeated for two glasses' types, becomes an other identity by similarity, so amplifying the strength of persuasion.

Of notable interest is the figure of the balance, with double scale's indexes placed to zero. The double numerical scales visually recall the form of the spectacles' lenses (identity on the attribute = metaphor). The balance's indexes placed to zero is a transmodal semantic hyperbole (identity by semantic similarity) on the word "leggero" = "light" and the analogical visual scale. There is also a third similarity of the semantic type as built on the number "two": Two reduced prices, two indexes showing zero.

The hidden opposition (a balance of that type does not exist) not only attracts the attention but it becomes even more persuading for the three inside similarities.

Very well done.