Definitions of subscription
an advance payment which is made to receive a magazine or other publication
According to the complaint, the telemarketers contacted consumers who already had subscriptions and pretended to be the company providing the magazines.
an arrangement where access to an on-line service is made available
The company also gave him four free games and a year-long subscription to Xbox Live.
the act of making a commitment to buy newly-issued shares (=shares offered for sale) in a company
In commercial terms, there is a very important distinction between a subscription for shares and a purchase of shares.