Buying a Sim Card

I can suggest Tomato network and their prepaid tariff for 49kn + 20kn activation for which you get 1000 minutes, 1000 SMS and 1GB data for the whole month. You can buy SIM card with 20kn credit on it for 20kn on any newstans, store, post office... it's cheap and you have no worries for using it in Croatia. But if you'll use it for calling abroad, that will cost you extra and that amount will be deducted from your current credit. So, when you buy SIM card package, don't forget to top it with 100 kunas, because you'll have to activate it and it will deduct 69kn ($12). The whole procedure can be found here: http://www.tomato.com.hr/en/brutalna-tarifa

There are other networks, but I'd say this is the cheapest solution for what you need.

Your hungarian sim is not working because you did not activate your Roaming service. Next time when you are in Hungary, go to any cell shop and explain in basic English (hungarians are notorius for not speaking any foreign language) that you want to make calls abroad and they will do it for you.

Thanks for the reply. I don't use the phone a lot so I don't really want to have to do this 49 kn per month. I would probably forget. Is there one with no monthly fee like I have in UK and Hungary?

you can buy just a sim card of any operator and just use top ups
but if you have smart phone and use internet on mobile, they suggestion from above is better solution

hi
You can buy a sim card over the counter at any t com shop