Gee it takes some interpretation to understand the question.
Most party's want to stay in power, The Tories can do so without any deals, but it is in the interest of the country to be able to govern not risk having legislation slung out every now and again.
The money isn't just being offered, it is to pay for things that are desired in society, the society that pays in to the public purse. The way you state it is seems to imply that the government is just slinging it the DUP way for their own benefit.
If there had been enough seats then the desires of the DUP would have taken more of a back seat, they now have the ability to ask for their priorities to be considered. It's an example of having power.