It means that you have plenty of money to spend right now. "Rich" usually means that you have plenty of money all the time. "Well-heeled" may mean that you're rich and you always have money, or it may just mean that you have plenty of money right now.

http://grammarist.com/usage/well-heeled/ ==>No one knows the exact origins of heeled in this use, but there are a few theories. One is that this sense of heeled has to do with shoes; a person who has nice shoes is well-heeled and hence well-off. Or our modern sense of well-heeled could come from mid-19th-century American-West slang, where well-heeled meant armed with a gun.