Thrifty Living: At last, a way for us poor, exploited punters to hit back

I'm fascinated by the new public ratings website, www.plebble.com, which enables the public to rate businesses for their service and value for money. Rather deliciously, supermarkets which reported the highest profits over Christmas (Morrisons, Sainsbury's and Tesco) are coming off rather badly in the Plebble chart, while good old Waitrose is riding high (probably because it's nice to chickens). The businesses that come out worst are the dreaded computer security system Symantec and Carphone Warehouse. Hooray! At long last, a public revolt against Carphone Warehouse's teeth-grinding queues, tortuous handsets and inexplicably enormous bills.

I log on to Plebble and, after giggling at all the postings by pissed-off customers, post my own grumpy thumbs-down. This, I don't mind telling you, goes to Books for Children, a so-called "club" that has the peerless sales technique of a) sending you boxes of unrequested books, and then b) charging you for the pleasure of returning them. If you phone to complain, you wait for a seizure-inducing length of time before the phone is answered by a friendly but powerless person at a "customer service" centre in India. I've written to BFC to beg for release (so far no response), but it felt good to slam it with a minus 5 Plebble rating, the lowest possible.

Could the site be abused? Aggrieved ex-employees or shareholders might find Plebble rather useful. But founder Will Paterson suggests not: "We verify each rating through an email check, and only allow one rating for a company per person." Apparently, the site's intriguing name, which Paterson and his brother James came up with, is a "generic invention" referring to "plebeian" – a Roman citizen who was not in the privileged patrician class. Does it have anything to do with a pebble, I wonder? "Er, no," Paterson says.

Never mind. Plebble may be a crazy name but it's a good notion, as it allows us, the precious customer, to easily and publicly vent our feelings. I aim to use it whenever I feel aggrieved at a ruinous service (Books for Children) or pleased with a value-added one (John Lewis, currently in at No 7).

Since my discovery of Plebble, I've developed my own system of ratings. Having been "let go" from reviewing plays for the New Statesman, as discussed last week, I've had to face the reality of actually paying to go to the theatre, rather than swanning into the foyers of Britain and claiming a lovely pair of comps. I know. Paying for tickets, just like everyone else has to. It's done me a world of good. I think all theatre critics should do it, even without the prior bother of being sacked. It radically changes the way you perceive a show.

Last week, I took my 10-year-old daughter to see High School Musical at the pointedly non-West End venue of the Churchill Theatre, Bromley. The ticket prices were pointedly West End, however, at £30 per person. As I gasped quietly at the till, I happened to notice a small sign indicating the Churchill offers of £5 concessions for children. Not with this show. "Disney offers no concessions whatsoever," said the lady in the box office. "I've been explaining this to people since November." She shrugged. "The show's still a sell-out."

We then negotiated our way past heaps of wildly expensive sweets and HSM goodies in the foyer, including four badges for £5, a mascot for £10 and £12 for an "I Love Troy" T-shirt. Hmm.

Was the show worth it? In a word, no. Not at £30 a pop. To be worth it, the show should have been "life-changing". This is the criterion offered by the arts guru Sir Brian McMaster. It is now my criterion. In his report, which influenced the Arts Council's latest round of awards and cuts, excellence is all. And excellence, in his view, means "life-changing". I now apply the McMaster Rating to all costly arts events.

Would it be "life-changing" for me to see Penelope Keith play Lady Bracknell in the current production of The Importance of Being Ernest? Well, it might be very nice, but life-changing? Probably not. Will it be life-changing to see Alistair McGowan as the Mikado? Again, probably not. And I haven't got the cash to waste on a low-rating night. Dear thrift-seeker, this system is a peerless money-saver. There's a lot of very mediocre stuff out there, and thus, so far, it's been a very cheap winter.