We have an 8 day midsize SUV rental through National using the KLM Flying Blue code found in this thread:
http://www.disboards.com/showthread.php?t=2878667&highlight=used+an+awesome+code+for+my+april+trip
plus a $25 coupon from the Entertainment Book for a final total, with tax, of $266.97.
In addition to unlimited miles, rentals with this code come with a whole bunch of extra insurances and coverages including:
Loss damage waiver full
Supplemental liability insurance
Airport access fee
Florida surcharge
Tire/battery fee
Vehicle license fee
Might be worth comparing with the
Budget code, as this one came out better (cost wise) and offered more for the price. Joining Flying Blue is free and open to anyone

.