Morning Shivvy!,
Well I have been cruising for the last three years, my in laws take the whole family (inc kids) because then everyone's happy.
We always go with P&O who set sail from Southampton. The trip consists of the Med .... we go for two weeks but they do a week's cruise too, (just to give you a taster) I'm 39, very outgoing and chatty and I love them!
The best ship I have been on was the Ventura, massive and lots to do. The staff are great, very, very helpful, and the ships are beautiful. Here is the website for P&O
http://www.pocruises.com/ most of their fleet are new ships, with up to date technology, i.e fully fitted gyms, spas, nice cabins with en suite, a number of pools.
The hidden costs are: alchohol drinks, tipping (usually done to your cabin steward at the end of your holiday) casino money and any excursions you may want to do. when you embark you get a ship's account card and at the end of your holiday you pay up, it's all very simple and easy.
Finally would sooooo recommend a cruise because you can do as little or as much as you want to do. the staff work really hard for your entertainment, nightly shows, parties on desk, films to watch, quiz's, talks on various subjects and the food is yummy, you don't have to lift a finger! plus you get to dock in a new place practically every day! upon departure they usually have a sail-away party on top desk which is always a hoot.
Really hope you go for it and I'm sure there are plenty of deals out there so haggle!!! maybe you can get your flights thrown in.
P.S. Don't go for the Thompson cruise cos their ships are tiddlers and you can't help but laugh when the P&O ships dock beside them! It's all about the status! and quality of passengers cos they really help to make your holiday better.
Hope this helps, will su