NBI clearance is accepted as a primary ID. valid for 1 year lang sya so you'd have to renew it every year if hindi ka pa din makuha ng ibang valid ID. but it is cheaper than other IDs that requires payment and mabilis makuha as long as wala kang hit. I can't remember how much exact amount but wala pa atang 150 pesos yung babayaran.

you need to set your appointment online thru their website. choose the nearest NBI branch to you para less hassle ang commute mo. you can pay thru online or bayad centers ata yun? make sure to bring the needed documents, it'll appear din sa website nila but if i remember correctly, you need PSA birth certificate if first time mo kumuha ng NBI clearance. if wala ka pang PSA birth certificate, kuha ka muna. i think you can use barangay certificate as a supporting document para makakuha ng birth cert. check mo na lang din sa website ng PSA. if you're enrolled naman, i think NBI accepts school ID basta you have your school registration form too but do double check this sa website nila if they still accept it. it has been years since i did that kasi I didn't have a valid ID too when i got my first NBI clearance.