Fold a dollar bill in half 50 times, and it will be thick enough to reach 80% of the way to the sun. Nineteen more times and it will reach Alpha Centauri A, the closest extrasolar star. One more time and it will stretch past Sirius A, or point in a different direction to go past Epsilon Eridani, a star with two planets. One more fold, 71, will take you past Gliese 876, which has four planets.
Folding it in half 101 times would bring you just short of the former location of UDFj-39546284, a galaxy (no longer existent) that is the most distant object ever observed. One more fold would take you just past the edge of the observable universe.
At this point, the cross-sectional area of the dollar bill would be 2.04 * 10-33 square meters, or about 10 by 10 Planck lengths (equivalent to about 10-18 times the size of a proton). The Planck length is the smallest distance that can have any meaning.
At 101 folds, the thickness of the dollar bill is now equivalent to 2,535,301,200,456,458,802,993,406,410,752 bills stacked on top of one another. If you actually had that many dollar bills, it would be enough to give $362,185,885,779,494,114,713.34 to every person on earth (assuming all of them are one-dollar-bills). This would be enough for each person to pay off the United States' national debt 22,636,617 times over, or once every second from January 1 to September 17. For 102 folds, double all these numbers.