To give away land you own, and as part of the deal you pay the person or entity you're giving the land to a considerable sum of money.
Example 1: I'm giving away half my garden to my neighbour, and paying him £10,000. The wife's not too happy, but I'm calling it, my Chagos Deal!
Example 2: Have you heard, the UK government is giving the Chagos Islands to Mauritius! In addition, as part of the deal, they are paying the Mauritius government in excess of £9 billion!