It depends on where it originates from, also it matters if it's a LDU OR RDU.
You can try some of these. If you can download any apps at all try "simple factory reset" from galaxy store.
Retailers
Walmart = rollback
Tracfone = halfthecost
Best Buy = blue
LG = 103729
Samsung = 5444
Huawei = 1122334455
Huawei 00CDIAGE
Other Passwords
galaxy
ruletheair
rethink
demomode exit
instoredemo
remove cod
nationwider
Samsung Settings
M729Q16K8546