Get Norwegian Cruise Line - Last Minute 14-Day Transatlantic $499 pp or 10-Day European $579 pp based on dbl occ (From $39 pp per day)

Norwegian Cruise Lines have several upcoming cruises on sale and limited inventory. Considering cruises are all inclusive (room, food, entertainment), these are two notable ones among many others on their website:

14-Day Transatlantic from Copenhagen [ncl.com] - Starting From $ 499 USD (or $39 per day)
CRUISE PORTS EMBARK Copenhagen (Denmark); Ponta Delgada (Azores); Royal Naval Dockyard (Bermuda); DISEMBARK Miami (Florida)

10-Day Canary Islands, Spain & Morocco from Barcelona (Variation) [ncl.com] - Starting From $579 - Now from $679
CRUISE PORTS EMBARK Barcelona (Spain); Casablanca (Morocco); Santa Cruz de Tenerife (Canary Islands); Las Palmas (Canary Islands); Funchal (Madeira); Granada (Malaga) (Spain); Alicante (Spain); DISEMBARK Barcelona (Spain)

Use Norwegian's site to view dates and itinerary and then book it on Expedia [expedia.com],
Priceline [priceline.com], Travelocity [travelocity.com]. Sometimes there are added incentive to book with them. Or simply book directly.