Usually, Vision Express charge $25 for an eye test. Personally, it is a little expensive. I find that taking eye exam at Boots only charge $20. And it is little lower at Specsavers where only require $19.50. Besides, the cheapest place i can find is Optical Express which signs that $15 for an eye test. Hope this help.
I have not had the eye exam at vision express. But you can go to the internet and search the answer. Or you may go to the vision online store to search the marked price. Or you can call the phone of the vision store to ask the client. Whatever the above way you use, you may get the answer quickly.