To dream that you are shopping symbolises your needs and desires. It also represents opportunities and options that you come across in life. Consider what you are shopping for and what needs you are try to fulfill. In particular, to dream that you are shopping for food and groceries signifies your hidden attempt to buy the attention of others. If you are shopping for clothes, then it suggests that you are trying to put forth a new image.
To dream that you cannot find what you are shopping for suggests that you are trying to find a solution to some life problem.
To dream that you are shopping for gifts for someone implies that you are looking or searching for acceptance.