cost has very little to do with putters IMHO. if a £10 from sports direct gets the ball in hole in the least shots, how is a £250 scotty cameron better FOR YOU? OK it may use more expensive materials, a high end brand name, hell even look nicer! all of that is irrelevant if suddenly you are in 3 putt city.
putters are all about feel, i couldn't give a monkies whether it cost £10 or £300 what worked best for me is the one i would want.
I am starting to ponder my putter, its not been behaving for some time, and when i bought it, i bought for brand and looks.. ok i hit it in the shop, it played OK, but i didnt try them all.. I am going to start looking for a new one and work work work at it. 6 x 3 putts at west hill and i still scored 30 points.. shows where my game needs most work!