Well then you've got to tell me where/how you book your vacations. They're certainly not cheap. A three-night Vegas trip (airfare + hotel + car rental) start at around $1,000 for two, and that doesn't even include dining, shopping, and entertainment. Cirque du Soleil shows cost about $100 per person.
Carribbean Cruise: straight from the source,
www.carnival.com. Deals can also be had through travel agents. Book anytime from Labor Day - Memorial Day (don't worry, the weather is great in the Carribbean and Mexico during the winter) excluding holidays. You'll find 7 day cruises in interior cabins for around $400/person. Stay away from summer time and holidays, because that's when families with kids are able to take vacations, and you don't want to A) pay the inflated peak season rates, or B) hang out with kids all week.
Airfare is on your own, but if you live in California you can drive to the port or park at a friend's house nearby, which is what we do. Like I said, the last time I went to the Carribbean I bought a $400 plane ticket to Ft. Lauderdale and spent $450 for my half of the room. This was the week before Thanksgiving.
Las Vegas: You're doing it wrong if you're renting a car. I drive in since I live close, but I could just as easily fly in and get a private limo from the Hotel, usually for free or cheap. Once my car hits the parking garage Friday afternoon, I don't see it again until Sunday night. If you're staying on the strip, you will NEVER need your car. If you gotta fly, that sucks, but flights to Vegas are among the cheapest flights to and from anywhere in the world.
For the hotels, join a players club and add up points from your gambling. If gambling isn't your thing, check out groupons or other discounted rates. Get on the casino's mailing list, and they'll send you discounted weekend rates a lot of times. I have stayed at hotels like the Planet Hollywood and the Mirage for damn near free before.
Cirque du Soleil and other Vegas shows: Same deal. Book online in advance for discounted rates. $100 is actually a great price for a show when you consider the fact that you could lose $100 in 20 minutes at a blackjack table.
Just like when you're buying a car, if you don't do your research then you're going to get hosed. Do your research, deals are out there, and don't get taken advantage of.