http://www.uzo.pt/pt/tarifario/pagina.uzo here it's clear: one recharge every 4 months. Perhaps Effendi could update the news in National operators?
[COLOR="Magenta"]"Working" PrePaids: Wind, Vodafone, CoopVoce, , Travelsim (2), 02 Irish (2)
My best sim?--> Wind +39-328
My phones:
Samsung Galaxy Next S5570