Don’t just look at the headline prices, see what the price gets you; a cruise that includes a drinks package, gratuities, even complimentary shuttle bus from ship to town, for example, can be better value in the long run.
i would go for a med cruise first off, ideally one with no tendering, and a stop every day, so if you’re really not enjoying the onboard experience, you can escape. Also, your mobile phone allowances might well be valid in Europe, although not while you’re at sea - onboard WiFi can be quite pricey, but again, you might find a package that includes some time.
Watch out for stops that have something in brackets, such as Rome (Civitivecchia) - the place in brackets will be the docking point; it will generally be a long way from the highlighted destination, and in the worst case scenario, might be a container port with nothing to do.
I’d strongly second @Jellifer‘s recommendation of Azamara, plenty included in the price, their ships really can get you into the thick of things, and their service has always been brilliant when we’ve sailed with them. It’s casual, no formal nights, and very relaxed on board.
Also, Saga was deeply disappointing. Avoid.