European political campaigns are usually cheaper than US ones, but they're by no means cheap in absolute terms. We have corruption scandals here too... before '92, a lot of political parties were almost entirely funded by either the US or the USSR; they've been economically struggling ever since.
We have Party Political Broadcasts in the UK, which are scheduled and appear in tv listings one party at a time. They are usually after the news, but not always, and regular programmes are shifted by 5-10 minutes to accommodate them.
At least I never seen anything like what Jon Stewart showed. There are political TV ads during the official campaigns, but that's two weeks before the elections and it's just 1h where the ads run all in a big block.