As others have indicated, you're free (as a self-employed worker) to charge what you like. If you're prepared to work for the equivalent of only half of the National Minimum Wage, there's nothing to stop you doing so (because the NMW legislation doesn't apply to self-employed people). Similarly, if you're working for Bill Gates as the only typist available to complete a vital document that MUST be finished within the next half hour, you could charge £10,000 per page if you thought that he's pay it ;-)
This commercial agency charges £3.50 per page:
http://www.fingertips...es_and_turnaround.htm
If you're working from home (and trying to see off any competition), £2.00 to £2.50 per page might be more reasonable. (It could also depend upon your location. Around here, in East Anglia, most office staff get £5.80 to £6.00 per hour. In some parts of London and the Home counties, an office typist might get more than double that).
Chris