1)producing indigenous equipment in some equipments, needs some start up costs. So, if a country does not want to produce them in large scale, indigenous production is nothing but loss of money. That's why Azerbaijan is focused in indigenously production of cheaper, but larger in extent products like rifles, which it absolutely makes sense. producing indigenous aircraft or maybe even tanks is not economically beneficial for Azeris.
2)ToT/Co developing needs less start up capital and then producing some armored vehicles, like Mbombe as Azeri440 has also mentioned, and I guess even tanks, helicopters and UAVs can be economically beneficial. Azeri440 has provided more details in his post.
3) rest of items need to be bought. like MIG29s, S-300PMU, ...
As purchases are concerned, Azerbaijan has bought about 100 of T-90 tanks, 100 of BMP3s, Russian mil-35s are bought as well, S-300PMU, and Tor have been bought. MIG-29 are bought from Ukraine, and many drones(like Herms-450, IAI Heron) are bought from Israel.
