if you're black,then doing it and toni and guy is such a waste of money, it's a new thing for them as not many salons do it,so they rip off people. you can easily go to black/asian salon and they'll do it cheaper and better.or if you go into superdrug, they sell the dark and lovely range for £3.99. all you need is a responsible careful friend (or you can do it yourself although it's harder), and do it at home. just remember to wash thoroughly etc.
hair relaxing is a thing done by either black/mixed people (who have afro-carribbean black hair) that involves mixing and putting on the hair which alters the structure of the hair,so it becomes straight, easily managed and just basically easier to handle.
there's a caucasian/asian equivalent which uses the same method but it takes longer. it takes about 6 hours in total as the the chemical is re-applied several times etc because the caucasian/asian hair is finer and not coarse like afro-carribbean hair. in this country it costs at least £90 at reputable places out to get your money as it's still a new procedure and not many people do it.again if you're asian, it's best to get it done at an asian salon where they have more experience. for caucasians, i know boots sell their own range which has the same purpose (not sure how much it costs though).