Do I have to wait to spend a cash gift from a parent

The moment your mother gave you the money it became your money so you can do anything you want to do with the money at any time.  I know of no five-year restriction on using a cash gift.  Go and enjoy your cash gift, but understand if your mother makes any other gifts to you this year, she will have a taxable gift. While a person must make $5 million in taxable gifts before they will owe any gift taxes, if a person gives more than $14,000 in 2013 to an individual, they will have a taxable gift for the amount over $14,000 and will be required to file a gift tax return.  So if your mother buys your dinner at McDonald's, she will have made a taxable gift to you for the cost of the dinner.  That's because she's already reached the maximum dollar amount she can give you this year.