But thankfully, The Bargain Queen stumbled across the London Times' Interactive Su Doku puzzles and does them online for free instead!
They're also in the Sydney Morning Herald, but you have to buy the paper to get them. Qantas and JetStar inflight magazines have them too, so they're free if you've already got a plane ticket. Or if you must buy a book, the airport is the worst place to get them. If you can stop at a regular newsagent beforehand, you'll pay about $4 instead of $10, and every little bit counts.