If your 10 Hosts are already licensed with vSphere ESXi than you need of course additional vSAN (3 editions available) licenses.
If not... depending on the use case of your Cluster several special Bundle or Addons are available.
VMware HCI Kit = 1 ESXi + 1 vSAN Lic
VMware vSAN Desktop = all inclusive bundle for VDI only
VMware vSAN ROBO = max 25vm per Site
External JBOD arent a valid configuration for VSAN (i only see some special for HPE Blade with external SAS)
Reuse of existing HW doesnt work well in most cases (for Lab or Testing maybe).
Regards,
Joerg