We printed both off the internet, and filled them in, got them witnessed and sent them off.
We had to pay (£50 I think)for the GP for certifying that she had capacity. However you can get people who have known them for over 2 years to do this bit.
You do need to consider carefully who should be appointed - in my mum's case myself and my brother are the only siblings and we can both act joint and severally.
What we didn't do was appoint replacement attorneys so that if one of us dies someone else can replace us, and we should have done.
As far as using a solicitor, they have an hourly charge out rate for staff at different levels, and they will spend time explaining it, making sure that all parties are happy and understand it and filling the forms for you, and registering them. The cost should be paid by the donor.
Most people pay a mechanic to change the car oil, and this is just paying for someone's time to do the work for you, with the backing of professional experience and insurance. I don't think the solicitor is deliberately trying to make a profit out of someone else's misery just providing a service.