I take your point, to a certain extent, but to me the meaning is pretty clear here. However, this time I tried "Do I need to buy it", which was accepted.
Incidentally, would the same go for this one, also translated with the infinitive?
"Tu crezi că e necesar să ai un telefon?"
Pronunciation issue here again. All forms of the verb A FI (to be) that begin with E, as well as all subject pronouns that begin in E deviate from the pronunciation norms and should be spoken with a [ye] at the beginning. Therefore E should sound [ye] as opposed to [eh].
This is also the case for words like EL, EA (he, she), which are pronounced [yel], [ya], or other forms of the verb A FI (to be) in present or imperfect such as ESTE [yes-teh], EȘTI [yesht], ERA [yeh-rah], etc.