Temporary Cell Phones Options

I'm in Zagreb for about 4 months and need a mobile phone.
I may have access to an older model that I've been told I can buy a SIM card for.
Any recommendations for service providers/plans/etc. I can look into?
I don't need the phone for much more than local texts and some local calls as well. I don't care too much about a smart phone as I have a much smarter laptop computer.

In Canada we don't have as many options to sort through :)

just take prepaid sim card, VIP network

Is anyone using nokia n series smart phone?