Ask around about a good plumber ,then you can buy what you want and get him to fit it or he can supply and fit . Make sure he is not wearing a cowboy hat !! Go on recommendation ,
Good Luck .
If you mean the price of the replacement toilet and sink it could be less than �100 to several hundreds depending on quality and size. Have a look at your local DIY say B&Q who may have a sale on.
For example the B&Q Azure Cloakroom Suite White/Chrome Effect(includes taps) is �109. Have a look at the web site
(www.diy.com)