Boomerang for Gmail just left beta, and is going to have paid plans, with the free option limited to 10 emails per month. They just sent an email out to beta testers with a discount code.
If you subscribe to a paid plan within 24 hours, using the coupon code betacustomer, you will save 40% off of your subscription until you cancel. If you subscribe before September, this coupon will save you 15%.
I received the email at 10:24PM AEST on the 14th, so 40% off will go till the same time tomorrow.
Boomerang is a pretty interesting plugin/extension for Firefox/Chrome/Outlook that lets you delay sending out an email, and other nifty stuff like returning an email to your inbox if no one responds. Check out their front page if you want more info, click on the "As featured on:" links on the left to read other "authoritative" write-ups.
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