より～のほうが can be thought of as similar to the grammar points
たほうがいい, and
ないほうがいい, in that it expresses that one thing is the ‘better (A)’, or ‘more (A)’. However, unlike ほうがいい based expressions, any pair of adjectives, verbs, or nouns may be compared in this construction, so long as
のほうが is followed by an adjective.
より translates roughly to ‘than’, or ‘rather than’ in this phrase.
-
田舎（いなか）に住（す）むより、都会（とかい）の方（ほう）がいい。
I like living in the city more than the countryside.
-
彼女（かのじょ）より、私（わたし）の方（ほう）が背（せ）が高（たか）い。
I am taller than my girlfriend.
-
映画（えいが）は怖（こわ）いより、面白（おもしろ）い方（ほう）が好（す）き。
I like funny movies more than scary movies.
From the examples listed here, we can see that
より will always appear after the word that has the lower extent of (A), when used together with
のほうが.
When
より is used by itself, or when it is not linked directly to the previous word, it can seem like it has the opposite meaning. However, in these cases,
のほうが just remains unsaid.
In this example, because the
より is after
が, not before
これ, it is easy to assume that
これ is the thing that is lower. However, this
が behaves in the same way as
のほうが, meaning that
これ itself is the more expensive thing, with
より just being used like ‘relatively’ (compared to many other things).