Since your budget is tight, check eBay, overstock.com, your local menswear store(sometimes they have inexpensive seconds or even used items) and thrift stores(you can always have the ugly shiny metal buttons replaced on an otherwise fine blazer inexpensively). Also there are some online tux shops that will sell a full basic ensemble for about $100. You also have the option to rent. I would recommend buying no matter which way you go, because a suit can be used in seperate pieces or together any time and a tux costs the same to rent as it does to buy now(assuming you aren't like me and have to make a fashion statement(but then my career will have plenty of black tie events) and go budget). Also, some Wal-Mart stores now carry suit seperates, as does JC Penny and Target. Ross may have something if you have one locally, and they are at deep discount. Another source for a basic black suit with a shirt and tie that offers payments is blair.com. There are plenty of options and you don't want to miss formal night, as that is typically when you have the best food served in the dining room. Enjoy your cruise.