Script with Paypal

Need a script made from scratch that does the following: we would need to be able to upload pin numbers in various denominations. for example, 100, 300 and 500 increments. these are live numbers or pins that would be in our database and thus need to be safeguarded. so then a user would make an account and fund it with their paypal account (like a bank) or login and use their paypal account to buy these increment pins at a price (we can change easily). then, they checkout and pay via paypal. we have a paypal business account already. then, a confirmation email is sent to us as admin and to the end user to confirm their payment. we would also like to have fraud safeguards in place. capturing IP numbers and anything else that would protect us as much as possible, as well as a good protection of the database of live pin numbers. once the pin number is sent, it needs to go out of the live database and to a used database as well somehow, so just in case there is a problem, we can track any issues. basically, we want to make a website that allows a user to simply go online and buy a load, 100, 300 and 500 unit increments as quickly as possible with as much fraud protection we can have.