You just need to buy the case and the Li-Ion battery. The Heltec Tracker board comes with some 2.54mm DIL pin-headers, a 1.0mm JST connector and a 433MHz antenna in the box. The pin headers are NOT fitted. Here’s a picture of mine deconstructed so you can see all the parts:
When the parts arrive you wil need to solder the other end of the JST 1.0mm connector (the bare wire end) to the BL-5C battery connector:
This comes with the case.
Dave