Fee based organizations offer the lowest rates:

• Founders Card (join here); https://www.sixt.com/partners/founderscard/
• Hotel Express Int'l (join here): https://www.sixt.com/partners/hotel-...ernational-en/
• Entrepreneurs Organization: (join here but membership fees are steep): https://www.sixt.com/partners/eo/

The following entities offer discounts without a fee (but usually at higher rates):

• Marriott: https://www.sixt.com/partners/hotel-marriotthotel-en/
• Best Western: https://www.sixt.com/partners/bestwestern/
• Accor: https://www.sixt.com/partners/allaccor/
• Kempinski; https://www.sixt.com/partners/kempinski/
• GHA Hotels: https://www.sixt.com/partners/gha/
• Small Luxury Hotels of the World: https://www.sixt.com/partners/slh/
• Living Hotels: https://www.sixt.com/partners/livinghotels/
• H Rewards: https://www.sixt.com/partners/hrewards_logo/
• American Airlines: https://www.sixt.com/partners/airlin...tage-en-promo/
• Finnair: https://www.sixt.com/partners/finnair/
• Emirates: https://www.sixt.com/partners/emirates-skywards/
• Lufthansa Miles & More: https://www.sixt.com/partners/milesandmore/
• Avianca LifeMiles: https://www.sixt.com/partners/lifemiles/

There are two other discount opptys:

• If you have a business mastercard you can get 10-15% off here: https://www.easysavingsspecials.com/...0736a/all/sixt
• ASmallWorld members get 400 free kms/miles per mo for Sixt+ monthly rentals: https://www.sixt.com/plus/2105123249/