Personally even for just mostly browsing the net. I wouldn't go for anything less than an i3 with 4GB of RAM.
Taking that into account...
http://www.ebuyer.com/700308-lenovo-e50 ... 80ja0132uk£249.99 for a Lenovo E50-70 Laptop with a i3-4030U CPU, 4GB of RAM and a 500GB HDD.
It may be possible to get something a little cheaper than that, that isn't terrible. But I personally recommend anyone I know buy a £150 laptop.