1. Too expensive. This encompasses several varieties, like the media in question being literally priced more than the person is willing to pay, or the pricing is acceptable, but the person can buy only one of several choices and wants to evaluate all before giving one their money.
2. The product is not offered for sale. This is sometimes literally that the product isn't available for sale in your country, or the product is not available in a useful form, e.g. it doesn't come with subtitles in your language, it won't work on your device, it requires a stable internet connection, which you don't have, etc.
3. For political reasons, to avoid supporting DRM.