Can I make a prepaid Skypeout call to a GSM mobile phone on Yesss network in Austria

[inquisitor]

Yesss, btw, is just a MVNO on the Orange Austria network. But as dg7feq noted there are indeed far cheaper VoIP services offering calls to Austrian mobile phones starting from € 0.01/min - for a tariff comparison of some VoIP brands of an Luxembourgian company called Dellmont (formerly Betamax) which many of us have been using for years visit betamax price comparison.