While the equipment can be somewhat expensive, in many areas rental shops can rent everything needed for reasonable sum. The most expensive item is most certainly the kayak. Other equipment needed would be:

• life vest
  
• wet suit
  
• paddle jacket
  
• paddle
• booties/shoes
• spray skirt
  
• sun block
  
• water (for drinking and paddling in)
  
• maps
  
• tide tables
  
• paddle float
  
• dry bag