Dear Diary
Average original price: N/A
Potential earnings: $200
While we couldn’t find the Dear Diary’s original price, we discovered that these secret-keepers could be worth $200 today. Girls used these devices to write down their thoughts and feelings without worrying about their parents reading them because there was a secret code that you had to put to open the diary. You can get $200 for the Dear Diary if you still have its original packaging.