If you're having issues purchasing using Google Play, here are some steps you can try:

1. Check if you're logged in with a valid Google account.

2. Open the Play Store and check for updates.

3. Double-check that you have a valid payment method set up on your Google account. If your primary payment method is a credit/debit card, verify with your credit/debit card provider that there are no restrictions on in-app or online purchases.

4. Make sure your user controls are set correctly and that you know your PIN if you have set one up. You can view and manage this in the Play Store app under Menu > Settings > User controls.

5. Verify that you are within range of a Wi-Fi router or base station. If you're using cellular data, make sure it's turned on.

6. Try resetting your wireless router by turning it off and then on again.

If you're still unable to make a purchase or connect, you might need to contact Google Support, as they may have blocked purchases on your account.