The PI T4 is regularly around £50 - in fact looking at my next three stays there I paid £46.50 for this evening, £48.50 for 1 March, £48.50 for 6 April etc.

But yes the overall point is there are many hotels around LHR at all price points, and all easily accessed by bus/tube. So it should just be a matter of picking one which meets your needs.