Which printing service to use?

Ive just launched an exciting new small business located in Gloucester. I want to carry out some leaflet distribution in the community to promote my business. I have looked all over at nearby print outlets but most of them look very expensive or even can not carry out the appropriate kind of print out. I am looking to get about 5000 folded booklets produced for the first marketing campaign. Might any one know of any decent websites to visit to have this printed?