Australia's constitution (S54 and S55) requires all appropriations bills to be only about appropriations ("supply", as we call it). Anything else in a money bill causes the entire bill to become invalid.

That and party discipline means that US-style horse-trading is much harder. There's still pork-barrelling, but it's driven by the party's assessment of which seats need to be shored up, rather than every single electorate getting bacon grease, squeaky or not.