Since we give Israel the money to "buy" our weapons, we're really giving (not selling) weapons to them.
It's a 70-year old design. They're not asking for the latest and most top secret stuff. Just one plane.
And, in 2012, with the most modern upgrades, Boeing was only gouging the taxpayers for $82m each. That's chicken feed. We can stop giving money to Burma for studies on transsexual turtles and save that much.
Sounds like it would have been a good deal for us even if they paid for it with our money. They would be the ones taking the risk rather than us putting a B2 and it crew at risk and Israel would be eradicating a facility that could produce a nuclear weapon that could someday be used against us. Pretty cheap means of eliminating a potentially devastating threat. Further if Obama was against it, it was probably a very good idea.