"Mnunue"

Translation: You should buy

[adilalibra1]

why not "Anunue" is M an object prefix?

[AGreatUserName]

Ununue = you [singular] should buy
Mnunue = you [plural] should buy

Anunue = s/he should buy

M is also an object prefix (equivalent of a-) and then the lack of a subject prefix would make this interpreted as an imperative, so this could also mean:

Mnunue! = Buy him/her!