On edit payment info it keeps asking me to (Please enter valid security code) I do and every time it says the same thing and It won't let me purchase

The message is a catch-all for any billing anomaly. Make sure you are using a valid credit (not debit) card and that all your billing information is correct.

Accepted payment methods vary by country. From Payment methods you can use in the iTunes Store, Mac App Store, App Store, and iBooks Store you can generally use any of the following:

• Credit cards
• Content codes
• Store credit, including iTunes Store Gift Cards, Gift Certificates, and Allowances
• ClickandBuy
• PayEase
• PayPal
• UnionPay (requires SMS PIN for setup)

This is what Apple says in

If your credit card company's records don't match your records in the iTunes Store

In most cases, this issue is caused by a formatting error in the billing address that you have provided. You can correct the issue by verifying that the information you have provided is correct, or by changing the format of your address to match the format that your credit card company has on file.

You can verify and/or modify your billing address by following these instructions:

1. On a computer, open iTunes. If you are signed in to iTunes, skip to step 4.

   Note: Verify that you are signed in to the correct iTunes account. If you are unsure which account you're signed into, choose Store > Sign Out and proceed to step 2.

2. Choose Store > Sign In.
3. Enter your account name and password, then click the Sign In button.
4. Choose Store > View Account.
5. Next to Payment Type, click the Edit button.
6. In the Edit Payment Information section, choose None.
7. Click the Done button at the bottom of the page.
8. Click the Edit Payment Information button again.
9. Enter your billing address exactly as it appears on your credit card statement.
10. Select your credit card type in the Edit Payment Information section.
11. Enter your credit card information, your card's security code, and the expiration date.
12. Click the Done button at the bottom of the page.

If the issue persists, contact your credit card company and verify that they and any company they use to process credit card authorizations have the correct information on file.