Note: It appears that at the time of this writing most if not all paid apps are experiencing technical difficulties when downloading -- on either the online Market or the phone -- so if you're having trouble getting one of the ten cent apps, we recommend taking a brief hiatus and coming back to try again a little bit later.
Update: The promo page has been updated and it looks like all of the apps are downloading just fine now. Head to the source link to get started.
Update 2: So it seems that Google Wallet is having issues staying live today, so it's quite possible that you'll continue to have issues purchasing your apps until the service is fully restored.
Update 3: If you ran into issues with Google Wallet today, you may be in for some freebies: Android Police is reporting that users who had their orders cancelled are being awarded free apps. Hit their link below for details.