Here's a few links to some PAT resources so you can read up on the topic and make an informed choice.

Wikipedia article on appliance testing.

http://en.wikipedia.org/wiki/PAT_Testing

HSE website with a wealth of publications on electrical saftey & testing.

http://www.hse.gov.uk/electricity/information/testing.htm

If you are after low price labels for your testing trying sourcing your own and pass the savings on to your customer we use:

http://www.mercianlabels.com/

We use Seward test equipment as we believe it to be the best on the market, find out more at

http://www.seaward.co.uk/products/portable-appliance-testing-equipment/pat-tester-kits