colorful and tasty condoms, dildos, porn, vibrators
definitely sweets and chocolate! you could go to Primark and get some cheap socks and hair bobbles, I love getting those and i'm 16! maybe some nail polish as well, and some cute friendship bracelets because they'd be perfect for summer. you can order those off eBay for ridiculously cheap prices, and i'm sure you can get them in Primark too.
Nail polish Chocolates and lollies (try and give each person their faves for a more personal touch) Lip balm/gloss A cute soap/something nice smelling A thank you for coming card
put in some silly plastic sunglasses, a cheap lip-gloss, some candy, and a thank you for coming card