Fitted 70sqm of engineered oak flooring for a customer a few weeks ago, they got it from B & Q.
They paid aprox £1100 for the floor boards fibre underlay and solid oak skirting.
Considering Howdens wanted £2300 for just the flooring I think it was a good deal, and tbh it was better stuff than Howdens gave me as a sample.
I wouldn't advise using carpet underlay if that's what you are planing to do, its to soft and the joints can get damaged over time. Had to take a floor up that someone had fitted like this and refit as the joints broke up in places.