This is a great wooden paddle from Amazon for $10.
This crop from Amazon for about $6. Absolutely not something that will last forever, but it's been working great on my ass after a little bit of leather moisturizer (one of the things that came in my Doc Martens care kit). I've had it for 3 months, and IMO it's already paid for itself. Works just fine till I can get a "good" one. :-)