I was reading Barbara Tuchman's The Zimmermann Telegram and she mentions that towards the end of the war, 1917 on, the British were borrowing enormous sums of money from the United States--so that they could afford to buy American munitions.
By this point, Germany was just as exhausted as the British. Maybe moreso. Without friendly former colonies to draw on, how was Germany paying for anything? Were they just self-sufficient enough to produce what they needed internally? I know that the United States frequently relies on war bonds and the like, but by 1917, surely there wasn't much blood left to be drawn from the German stone.
Were they just self-sufficient enough to produce what they needed internally?
Essentially; remember that they also had their Austro-Hungarian and Bulgarian allied, and the Turks, as well as occupied France, Belgium, and the rest of Europe. It must, however, be noted that the quality and quantity of German production was well below what the Allies could manage.
Maybe more so
The British were nowhere near the situation Germany was in, ie starvation on the horizon. By Summer, 1917, losses to U-boats were down before the convoys were even introduced, while the grain surplus in the UK precluded anything worse than rationing.
how was Germany paying for anything?
/u/elos_ has answered extensively on this, but essentially by taking the Mark off the Gold standard and simply printing more. They hyperinflated their own currency and borrowed from their own banks, thus ensuring a monetary crisis after the war.