as for Italy, if you go to the pub/bar a 0.5l coke costs anywhere between about 2.50 and 4.50€ (at this pub I usually go to in Ferrara a medium coke costs 4.20 when it's a football game night and 3.60 otherwise). Beer I don't usually drink but about the same as coke (possibly slightly more). Mcdonald's I haven't gone in ages but a meal should be around 5-5.50€. But if you go to Italy stay away from McD's and all that

The North is quite more expensive than the Center/South and Islands (the Center/South being anywhere south of Emilia
-Romagna and Liguria: Massa,Pisa, Lucca, Florence, Ancona and southwards).

(if you're not sure where these cities/regions are located, take a look here for example) http://www.focusmm.com/italy/it_map.htm

Resort destinations in the summer may be more expensive as well

Whereabouts in Italy do you plan on going?