Ebay offers Intex Twin Air Mattress for $19.99 (reg $49.99) with free shipping.

Product Description:
The INTEX 18in Twin Mid-Rise Airbed provides enhanced comfort, stability, and support. You or your guests will appreciate the raised height providing easy accessibility and a closer feel to a traditional mattress. Experience a restful night sleep with the soft, velvety sleeping surface for enhanced relaxation. Easy and convenient, the powerful internal pump allows for quick inflation and deflation.

• Dimensions (Overall): 18 Inches (H) x 39 Inches (W) x 75 Inches (D)
• Weight: 11.2 Pounds
• Holds up to: 300 Pounds
• Dimensions (Packed): 12.25 Inches (H) x 14.25 Inches (W) x 8.5 Inches (D)
• Air pump type: Electric Pump
• Features: Adjustable, Indoor/Outdoor Use, Built-In Pillow, Folds, Inflatable, Built-In Air Pump, Outdoor Use, Indoor Use
• Height Type: Double High
• CPSC Choking Hazard Warnings: Choking_hazard_small_parts
• Includes: Electric Pump, Repair Patch, Built-In Pump, Storage Bag
• Material: PVC (Polyvinyl Chloride)
• Battery: No Battery Used