The IB Economics Syllabus (2005) requires you to understand:

Types of aid
• bilateral, multilateral
• grant aid, soft loans
• official aid
• tied aid

Image: Some rights reserved by Oxfam East Africa

You can quite quickly find out what these mean by visiting these websites:

BBC Bitesize Types of Aid (Geography GCSE website)

Types of Aid by Scalloway.org.uk

PDF file – AID – what are the different types? by World Vision Australia School Resources