cigarettes - €3.50 ish for 20

bottled water,beer and wine - do you mean in a shop or in a bar/restaurant ?

in a shop - these are Gozo prices - hopefully not too much more in St Julians...

water - €2 - 2.50 for 12 litres (6 bottles)
beer - 50c per 0.5l can
wine - depends on type, but reasonable local is €2-5 per bottle

In a bar or restaurant how much would it cost? And how much roughly to eat out, say for a couple of bowls of pasta and a bottle of wine?

Beer - pint of Cisk €2-€3
Pizza/pasta - €6-€8
Fresh fish - €12-€16 (Sea Bass, Grouper, Dorado, etc)
Wine - €9 - upwards but normally for €10-€12 euros in a restuarant you can get a good local wine.

It really depends where you go. If it's in the Hilton then more of course but the quality there is superb and we've never been dissappointed.
However, the above prices cover most ofthe restaurants in the St Julians area. Noticeably cheaper that the UK (London area) and also with a much better view and weather