Search for paracetamol
here to get more details.
Acetalgin
Becetamol
Dafalgan
Dolprone
Treuphadol
They should all be over the counter drugs. Paracetamol-caffeine-drugs aren't offered often, and personally I'd only recommend them if you have to drive a car afterwards...
Of course the cheapest way to get paracetamol is to join the Swiss army, where one is only sick if he has fever and the treatment to all illness is to fight the fever!

They use big volumes of paracetamol and Ponstan 500 (also called "Spontan 500" in these circles

) there...