I have an old Sony mega boost cd/tape player and one of the speakers 100mm 2.7 watts is blown. Does anyone know of a hi-fi place that sells replacement speakers.

I would visit MediaMarkt and look under Hangszóró (Speakers). Alternatively, a local electronics shop (electronika bolt) or even a local should know of a place. In Szeged we could even go into a PC (Computer) shop as they tinker with such equipment too.