Car rental
per Clark Howard;
‘17 rent thru Costco (Sams?) book ASAP check online a few times for a rate decrease
AutoSlash(.com) (‘17 MMM) You can either make a reservation directly with them, or import one you've already made elsewhere. They automatically track for price drops, and automatically rebook (if the lower price is for the same company & car size) or send you an email with easy instructions for manual rebooking (if the lower price is with a different company and/or car size). AutoSlash is not a rental car company themselves, they are a front-end booking agent/interface to all the major rental car brands. I've just saved anywhere from $40 to $100 per rental
Also; most major cities have some sort of 'rent-a-wreck'