Taiwan has purchased 171 American Stinger ground-to-air missiles, modified for air-to-air use. The Taiwanese are using these on their AH-64 gunships. The missiles cost about $200,000 each. Taiwan is also buying air-to-air launcher containers, plus test and training equipment. The entire bill will be $45.3 million.
A modified Stinger, for air-to-air use, was developed in the late 1990s. The most likely target is other helicopters, and the ATAS (air-to-air Stinger) can do that as far away as eight kilometers. Nailing a jet is more difficult (they don't call them "fast movers" for nothing). The ATAS can only reach moving targets at up to 4.5 kilometers away. In any event, that's not too bad for a 35 pound missile.
Taiwan would have about 60 AH-64s operational if the Chinese ever tried to invade.