There are four main DNA companies selling autosomal DNA test kits: MyHeritage, FamilyTreeDNA, 23andMe and Ancestry. Essentially, they are genetic genealogy test labs who are building their own databases based in America and Europe. They usually cost around $45-150 USD, depending on seasonal discounts, and can be in the form of either a cheek swab of saliva sample.
Most people buy the test online, open an account with the company, receive the test kit, take the sample, then send the sample back to their lab (sometimes cost prepaid). Once the sample is processed, it is automatically compared to others in that particular database. DNACambodia's purpose is to provide free test kits to people in Cambodia, who are looking for missing family members, but could not afford a test.
Please also read our DNA Testing page.