[Manabi]

Amazon has a special Valentine's deal on Kindle Unlimited. If you prepay for a subscription of 6 months, 12 months or 24 months, you'll save 25% off the regular price of $9.99 a month. (Making it roughly $7.49 a month.) This deal is good through February 14th, 11:59pm Pacific.

• 6 Months: Regularly $59.94 - Now $44.95
• 12 Months: Regularly $119.88 - Now $89.91
• 24 Months: Regularly $239.76 - Now $179.82

The terms also say that existing Kindle Unlimited monthly subscribers are eligible as long as they have not had a pre-paid subscription in the past:

Existing Kindle Unlimited subscribers with monthly subscriptions who have not previously purchased a pre-paid plan are eligible for this promotion. For those subscribers who choose to participate, automatic renewals will be temporarily suspended for the duration of the monthly package purchased and will automatically restart at its conclusion.

It's also limited to one per customer and one per account. Full terms are below in the spoiler:

Spoiler:

• Offer expires at 11:59 p.m. (PT) February, 14, 2016.
• Offer only applies to pre-paid Kindle Unlimited subscriptions.
• Offer does not apply to physical goods or individual digital content.
• Offer is only be available to customers located in the U.S. and is subject to the Kindle Unlimited Terms of Use.
• Offer limited to one per customer and account.
• Offer may not be combined with other offers.
• The maximum benefit you may receive from this offer is $59.94.
• The maximum benefit you may receive from this offer is one item.
• Amazon reserves the right to modify or cancel the offer at any time.
• Customers who are on a monthly plan and have previously purchased a pre-paid plan that is currently associated with their account and customers who have purchased multiple pre-paid plans that are currently associated with their account are not eligible.
• Existing Kindle Unlimited subscribers with monthly subscriptions who have not previously purchased a pre-paid plan are eligible for this promotion. For those subscribers who choose to participate, automatic renewals will be temporarily suspended for the duration of the monthly package purchased and will automatically restart at its conclusion.
• Offer is non-transferable and may not be resold.
• If you gift a pre-paid subscription plan purchased via this offer and it is returned, your refund will equal the amount you paid for the subscription, subject to applicable refund policies.
• If you violate any of these terms, the offer will be invalid.