Just got back on Tuesday after a couple of weeks in Porec.
First trip to Croatia - found it a wonderful country.
Typical bar price for 0.5L Karlovacko beer is 20 kuna - ie about £2.40. Cost of a 0.5L can in supermarket is 9 kuna - ie just over £1
Wine - I reckon local Croatian wine is generally excellent quality - 0.1L glass in a bar was around 12 kuna, but I found I could visit the local supermarket and get a really nice 0.75L bottle of red for just 29 kuna - amazingly less than £4 !!
Meals - very variable prices dependent upon where you eat.
It's not really cheap - but maybe somewhat lower than you would expect to pay in say Greece or Spain this year. Looking at supermarket food prices - they are very similar to those you would see in Tescos in the UK. That makes life pretty hard for the average Croatian people who earn very little. For example, hotel staff can earn as little as £200 per month, a coach driver earns maybe £800 per month - provided he works 7 days a week.

The exchange rate in my hotel was 8.4 kuna to the UK pound - which makes it quite a bit better than getting currency here in the UK.

Hope this helps - have a great holiday!