Why does my Buy Now Link just spin or not work?
Buy now links do not yet support products with required variations. If you click a buy now link and it appears not to work it is probably because the product requires one or more of the variations to be selected. To solve this problem you can create a new version of your product that is preconfigured to have certain variations already applied.
For example, if you are selling shirts and you require someone to pick the size of the shirt before purchasing it, you could create a new product that is a "Large shirt" with no variations. Then that product can have a "buy now" link since you define the size in the product itself - not as a variation.