Well.....................
I have tiled for as low as £20 per sq metre labour only for builders. Usually I charge between £25 and £30 incl for ceramic. £30 to £35 for porcelain incl. And £40 to £50 incl for stone.All depends how busy I am, if I want the job or not, if I think the customer will pay more, if the job is on recommend or not, if they are buying tiles with my discount.
In my view there is no average - just what each tiler feels he needs to earn / or can get away with ( you are not ripping a customer off by charging £35 per metre for ceramic if you do a good job and they are well pleased with the end result )
With regads to business cards- I have my home and mobile numbers and also address on the cards. I feel that it gives the customer more confidence that you are not a fly by night tiler. My cards are printed both sides so plenty of space.