Shanna and I went on a cruise to Hawaii a few years ago. We had to scrape a bit to pay for the tickets, but we thought once we were aboard, we'd be able to relax and have a good time.
It turned out that most amenities and activities carried a prohibitively high price: $5 for a bottle of beer, $400 per person for fun shore activities, etc. The money we paid to get on board was really just the start of a long series of higher-than-average expenses.
I'm reminded of this whenever I see a really nice car and think, Gee, maybe I could scrape together some cash and get something like that! Then I read today that a single Lexus ES headlight is $1,000. Ouch.