It's mainly about the $ increase, yes they will increase price of older stock as well, that's how business is done. When large stores like Metro etc. can increase price of products (retail price being higher than printed price of older stock, personally happened to me) then why do we blame the local shopkeepers? Contrary to the popular belief not all of them are rip offs, some are merely trying to earn a living.
You can convert $ 300 to local currency and will find the PS4 priced relatively competitively, do keep in mind that PS4 is majorly imported through gray channels, you can check PS4 price with Sony outlet to find the actual local price (if it's being officially sold here).