into the bargain

Momoは沢山の友人ができましたが、特に二人と仲良くなり、Beppoはその一人です。
Beppo lived near the amphitheatre in a home-made shack built of bricks, corrugated iron and tar paper. He was not much taller than Momo, being an exceptionally small man and bent-backed into the bargain.
慣用句らしい "into the bargain" の意味が分からないので辞書で調べます。
・Oxford English Dictionary: In addition to what was expected; moreover: an upstate yokel and a raving paranoiac into the bargain
・Merriam-Webster's Online Dictionary: besides :tastes good and is good for you, into the bargain