Alicia, one of our regular commenters (or our only regular commenter), suggested a catechism by Cardinal Gasparri. It seems to be about 40-60 years old depending on the version you find. I did a search at abebooks.com and found a bunch of titles for Gasparri. The book is called Catholic Catechism and seems to run at about $10 there. Some copies may be lower, some higher.