Clip In Extension Recommendations

Based on the styles I like for my bridal hair, I’ll need to add some volume and length to my hair. Since I’ll only use them for my wedding, my stylist said I can order clip in human hair extensions off Amazon. I’m super confused about the “grams” and such. I was hoping to spend no more than $60 on a pack of 18”. Anyone have brands they have tried and recommend? Or other tips for picking the extensions out?