Scott- He loves to get things for you like necklaces and bracelets. So for your birthday he got you a anchor necklace. He had your name imprinted onto it. It was to remind you that you are his anchor.
Stiles- He liked shopping for you. He always had the best ideas on what to get you. So on your birthday he got you some flowers, a big teddy bear, and also a necklace. The necklace had his and your initials on it and it was in the shape of a heart.
Derek- He hated shopping, so he just brought you to different stores to pick out what you wanted.
Isaac- He never has any ideas on what to get you. He always thinks that he is going to get you the wrong things, so he just brings you to your favourite stores so you can pick out what you want.