Any size of account is available for personal, group, school, or college use. Each test uses a specific number of credits, which is noted near the description for the test, and calculated as the number of questions in the test divided by 4.  Each time a test is obtained, questions are randomly selected from those available for the test, and the required number of credits will be deducted from your account.  If the same test is obtained multiple times, a different random selection of questions will appear, though some may be questions you have already seen.  Schools or large organizations may also be interested in our unlimited annual accounts - contact us for details.