Put them to Work
Surely there are plenty of things that a pure sentience can do that could be profitable, and even if they spent all their money, if they can make a little more scratch on the side they can stay {alive} longer. Now it may seem backwards to pay them when you want to make money, but obviously you get a cut of any profits they make whilst using your servers to do work (possibly a very large cut)... If you can find lucrative enough applications they could end up making you a ton of money.
Some example jobs:
- News Anchor or Sports Color Commentator {Max Headroom}
- Personal Assistant/Secretary {Cortana/Siri}
- Theoretical Scientist {Stephen Hawking would let being dead stop him from working}
- Stock Broker
- Tech Support