Not sure if this offer is in all Asda stores, but bought my PS3 slim 250gb today for £230 (labelled £240 in the games section but scanned as £230) which is quite a drop from regular £282 in Asda.
This was the Asda next to Trafford Centre - Manchester
So it might be worth checking your local Asda if you are thinking of buying one! :-)
- Checked another Asda (Hulme - Manchester) and it did not have this offer but had £217 for PS3 Slim 120gb when you buy a top 25 chart game.