The price of drinks all depends what cruiseline you go with but regarding tips - they're normally about £5 pp per day. It can work out to be expensive but don't worry - they are no means essential, ie. you don't have to pay tips if you don't want to. The tips will accumulate on your on board account every day and they will appear on your bill at the end of your cruise. If you don't want to pay them simply tell the Purser/receptionist at the help desk and they'll take them off your bill. You may want to reward the people that directly served you - your cabin steward for example - so just ask reception for a couple of envelopes so you give some cash directly. Some cruiselines actually include tips or don't expect them. Call cruise.co.uk for more details.