SEATTLE — Amazon is introducing new options to subscribe to its Prime membership service on a monthly basis, a change that could make the company’s video service a tougher competitor to Netflix.

On Sunday evening, the company notified visitors to its website that it now offers two new Prime price plans, the first of which costs customers $8.99 a month to stream movies and television shows from a new video-only version of its Prime service. A second new plan, priced at $10.99 a month, will provide access to the full benefits of the Prime service, including video streaming, free two-day shipping on Amazon orders, music streaming and other services.

Amazon Prime, by most accounts, has been a huge success for the company, but one of the biggest hurdles for anyone thinking about joining the service is that it has required customers to pay $99 up front for an annual membership. The new options do away with the need for an annual commitment to Prime, widening its appeal to people who are more comfortable joining it on a short-term basis.

The new monthly options will not save people money, though. Customers who subscribe month-to-month for the full Prime service will pay $32.88 more a year than if they subscribe on an annual basis, while subscribers to the video service will pay $8.88 more a year while getting substantially fewer benefits, like free two-day shipping, than annual Prime members.