On the consumer end, there is quite a fair bit of transparency. You can compare credit cards fairly easily on the websites of all the different institutions that issue the cards.
When it comes to merchants, the debit and credit card code of conduct promotes a lot of the transparency and requires that payment processors notify their merchants in advance when anything is going to change related to pricing or anything else.
The debit and credit card code of conduct underwent a recent update that will improve transparency even more, compared to where things were at not too long ago.