During my month-long stay in St. Louis I was billeted in Crowne Plaza - St. Louis Airport, in Bridgeton, MO. The hotel is located less than a mile from the Lambert International Airport, and is accessible from I-70.
Amenities include a gym, pool and jacuzzi at the lower ground level, free WiFi access on the lobby and in the rooms, a business center, same-day laundry and executive lounge.
A TGIF restaurant is also located inside the hotel, and stores such as Schnuck's, Walmart and Target are located within 3 miles of the hotel. You may request the hotel's shuttle to ferry you to any destination within five mile radius for free (just tip the driver)
Useful info: website and contact no: (314) 291.6700; daily rates starts at about $100