@Nathen-Simms You can also export as WAV and use an extral WAV to MP3 encoder.
If you cannot pay with your coupon or credit card it is likely that the coupon cannot be used for this feature and your credit card company doesn't support certain security features needed to process the payment. You can contact infoservice@magix.net to ask for more details or you should contact your credit card provider.
Assuming you are using Windows 10, for MP3 export you need Windows Media Player installed - if it is not installed got Windows settings, Apps & features, Optional features, Add a feature, select it from the listand install it.