Should i get a breast pump before or after baby is born?

Hi mummies, FTM here seeking for your advice. I am still considering whether to get a breast pump now or should i wait until baby is out? Reason being, i’m not sure if i have/have enough supply for BM, will i end up giving FM to baby? If yes, that will be a waste of $ to get a pump if i don’t really get to use it. Do you mummies get a breast pump before or after baby is born? Also, any tips to look out for a suitable breast pump? Thank you!