Alwaleed's message was popular: It was retweeted at least 28,000 times. But perhaps it was a little too popular. The account has now deleted the tweet, offering no explanation of whether the deal was still on, or why it was tweeted in the first place. Screenshots of the tweet are all that remain.
The decision to delete the tweet may be a reflection of some of the responses to Alwaleed's message, many of which mocked the opulence of the gesture.
However, while some showed support for the prince's message, many criticized it. For example, some Saudis, like blogger Essam Alzamil, argued that the Bentley offer showed that Saudi royals had no regard for the damage caused by the bombing campaign (at least 944 people were killed in "Decisive Storm," and thousands more were injured).
Others pointed out that the money would be better spent on hospitals and health care.
There were critics in Yemen, too, where those who had seen the devastation complained that those who had wrought the damage were now being rewarded.
Critics all around the world soon chimed in.
In the Saudi press there are reports that Alwaleed's Twitter account had been hacked, though the prince has not officially commented. A number noted that members of the Saudi military are barred from receiving gifts for performing their duties.
And just last year, he was reported to have bought 25 Bentleys for members of Saudi football team Nasr FC after they won the league.