This website has students/teachers rebate scheme for lodging.

Some good hotels in walking distance to the conference site:

• Courtyard Columbia Downtown at USC. (AAA Diamonds: 3. 10-15 minutes walking to the conference site and the mathematics department.)
  Telephone: (803) 799-7800. Please refer to the USC Math Department. Blocks of rooms have been reserved at a special rate ($95 + tax per night) including parking for the nights of April 3-5.
• Clarion Hotel Downtown. (AAA Diamonds: 3. 10 minutes walking to the conference site and the mathematics department.)
  Telephone: (803) 771-8711 or (800) 277-8711. Please refer to the USC Math Department. Blocks of rooms have been reserved at a special rate ($87 + tax per night) including parking for the nights of April 3-5.
• The Inn at USC . (5 minutes walking to the conference site and the mathematics department.)