I would say that in Prague all the hip places have them, they are also quite popular in Sofia (this is what I had on New Year's Eve as I was on antibiotics), though there are still a few nice bars with Pepsi/Coke. I would presume that this is the case in most of the Eastern EU. The small towns and classic pubs usually got Kofola/Derby or some other cheap local alternative. Btw the manufacturing price of soda is almost negligible.