This probably isn’t free money, since this stimulus package sounds a lot like the one Bush did earlier in his presidency. These “tax rebates” only appear to be early tax refunds on the following year’s taxes.
If thats the case these rebates are just short term, interest free loans.
(This is what the original poster said as well-but its a good point. This isn’t free money and yes, you could give it to charity. But do you normally borrow money to give to charity?)