In 661 B.C., the state of Wey was invaded by a nomdaic invasion of Di tribes. Their prince and armies were slaughtered in combat, and reportedly only 5000 refugees made it to their last holdout. The hegemonic state of Qi stepped in at this point, and sent an army to liberate their country from the Di occupiers. It subsequently supplied money, materials and labour to both build a new capital city for Wey survivors, as well as replenish their animal stocks. These actions were considered to have saved the state of Wey, which subsequently survived to 209 B.C. until the Qin Dynasty finally abolished it.
That's the earliest example of economic support after military rescue I can think of.
The above example involved two ancient Chinese states. A much more recent, but still very old, example involving two distinct peoples might be Japan and the Korean state of Baekje. In A.D. 660, the combined forces of the Chinese Tang Dynasty and the Korean state of Silla.
Japan sent an expeditionary army to save the Baekje state; when that failed, it re-settled Baekje's leading citizens without Japan. That's essentially offering long term economic support to the defeated refugees of Baekje. Also, it would have been an liberation in the same style as the question had it worked.