This is National's airport rental desk (downtown would've been more convenient, but prices appear to substantially higher).
Best straight rate on Nationalcar.com is $56.07 (pre-tax and fees) .... their website also offers a $20 off discount for weekends, so that would come down to $36.07.
Daily rate difference: $36.07 National vs $17 Priceline via BFT.
thanks again to BFT!!