How can the contraceptive sponge be obtained?

The contraceptive sponge can be obtained by purchasing it at a pharmacy, which is the correct option. This method of acquisition is accessible to individuals, allowing them to buy the sponge over-the-counter without the need for a prescription. Pharmacies typically carry various contraceptive options, including the sponge, making it straightforward for consumers to obtain it directly.

The other options do not accurately represent how the sponge is typically acquired. While some contraceptives may require prescriptions or online subscriptions, the sponge is available for immediate purchase without any of those requirements. Vending machines are not a common distribution method for contraceptive sponges, as they are usually sold in more regulated environments like pharmacies.