1. Is at least one of you over age 25? There are usually extra charges of $40 to $50 US dollars per day for underage drivers.
2. Even without the underage surcharge, two of you would probably save money by taking the train. You will have rental fees, extra charges for each country you travel in, drop off fees, parking (more than your hostel room in most cities), tolls and fuel (at least double the US price, more in some places), plus a variety of other surcharges, fees and taxes. In some countries, I think the theft insurance is required. You don’t have to buy the extra insurance, but if you don’t the rental company may tie up an extra amount of your available credit until you safely return the car. You can get a good idea of basic budget for the car and extras by using expedia or orbitz — just be sure to read all the fine print.

I like to rent a car to explore non-urban places, but I consider it a luxury. Basic city to city transportation is faster, cheaper and more comfortable by train. In some ways it’s even more convenient — city center to city center and you don’t have to avoid rush hour.

Rental rates vary a lot. It’s impossible to say “how much…” until you shop around. As OL already pointed out this trip is likely to get prohibitively expensive regardless of the rental rate. There may be restrictions against taking the car to Croatia and/or Slovenia. Not to mention that driving in a foreign country is a lot more stressful at first then going by train.

Hey guys Thanks alot! I was hoping i could drive through europe, but i hearing what you have to say and talking to some agencies i’ve found it to be expensive and no less time consumming! I’ll look into taking the train! Thanks again!