3 has started paying customers who sign up friends and family a whole pukka fiver for every subscriber recruited.
Said subscribers will have to put their (free) SIM into a 3G phone, and top up with some credit too. Once they've done so they get another couple of quid in credit, and the person who supplied them with the SIM gets a fiver dropped into their PayPal account.
Customer acquisition is one of the most expensive parts of the mobile business. Operators will happily spend hundreds of pounds (generally in handset subsidies) to get a profitable customer, and even a cheapskate pre-paid customer is worth a lot more than seven quid.
But it still compares well to O2's giffgaff promise of account credit, and 3 is promising a Facebook widget as well as on-line toolkit for keeping track of one's sales and commission payments - in case you happen to know a lot of people interested in changing networks.
For the mathematically challenged 3's Head of Online even spells it out: "Get 10 friends signed up and topped up and that’s £50 in your pocket" - though obviously you'll want to declare, and pay tax, on those earnings.
Bribing people to sign up friends and relatives isn't new, but paying them in hard cash is in the UK. It's very risk-free for 3, and therefore will quickly attract competing offers if it shows any sign of being successful. ®