Secret Santa
Step 2

Once you have all the names of people participating you need someone who isn't taking part to randomly select Secret Santas for each particpant so every member will be buying 1 present and receiving 1 present from someone else (their Secret Santa).
For example: Minako, Usagi and Luna are going to do a Secret Santa. Artemis writes their names down and tosses them in a hat. He then draws each name out to assign Secret Santas. Usagi will buy a gift for Minako, Minako will buy a gift for Luna and Luna will buy a gift (be the Secret Santa) for Usagi. Noone tells anyone who they're buying their gift for.

Step 1 / Step 2 / Step 3