eBay has periodically been offering coupons where they cover eg. 10% off of arbitrary items up to $100 total discount. Happened to be shopping for a synth on a day I noticed one of those so it worked out. Maybe there's somewhere you can get notification of it?
Hm, speaking of notification, camelcamelcamel.com is a site that lets you get notified when an Amazon item goes below a price you specify and you can see the historical price over the last year to judge if the current price is about as good as you're going to get.