Originally in the aspect of putting Dayton Rims on an old car, the term has grown other aspects.
In all usage, the term is used to describe making something better with a bit of cash flow. Such things are used every day, from tipping a waiter/waitress so
one may accquire good service, to putting money into
one's
computer network to make it better.
"I had to throw some D's at that
sucker just so he could serve me"
"Man, that's
one shitty cell
phone... you aughta throw some D's at that, sucka!"