This is EASY MONEY if you are quick and reliable.
I have an asterisk box all setup, so you just need to make a script to do the following with asterisk (I actually even have the user interface code and DB done, if you need it)
1) ask person for telephone number
2) ask person for time/date
3) Ask person to select Wake up message
4) Take payment
People will pay PER wake up call, each time...no member login needed
After payment, code/db will connect with asterisk and tell it to dial the number entered on the date selected and play the audio file selected
I will not consider placeholder bids - please say the word "asterisk" in your bid so I know you read and understand this.