The price for hiring a Blue Badge Guide varies from region to region, with London being the most expensive. It will also depend how long you require a guide for – booking a Blue Badge Guide for a 10 day tour will work out cheaper per day than booking for just one day. Tours in a language other than English are generally more expensive.
The best way to find out specific prices is to contact the guide, talk to them about what you want and let them give you their price.