About 2/3rds of UK prices is about the norm. couple of quid for a beer.
Drink croatian wine instead, it’s mostly lovely, interesting and super cheap.
Swanky bars selling international spirits and beers etc will be the most expensive obv. Croatia is doing quite well for itself, so there’s a lot of young people with disposable incomes and tourists who want somewhere nice to drink…so some places can seem oddly expensive for Croatia. You’ll be able to spot them though, and even then they’re not more expensive than pricey places in the UK.