Q: We are going to London on the 9th of April to the 12th, we want to see a fotbol match,do you know where they are and how much a ticket costs?
A: have a look at the link below, which shows what matches are on during the time you will be in London.
Then, I suggest you contact the home club for the match you want to see and try and get tickets through them. This is likely to be cheaper for you than buying them through the web site linked above. (If any tickets are available.)