This Saturday’s “Extreme Couponing 101” workshop at the leisure centre in Lexington, South Carolina, is entirely booked out, with 30 people paying $10 each for a two-hour course in how to save money when shopping.

The event is organised by Jenny, the author of Southern Savers, one of a plethora of online blogs devoted to the art of saving money when shopping, traditionally by clipping the coupons delivered each weekend with the local newspaper.