Impulsive buying behaviour is a form of unplanned purchase that happens on the spot without any former intention. It is most commonly triggered by some kind of stimuli in a form of external or internal factors. This buying behaviour has no buying pattern and no decision-making process which is why it is impossible to dissect this type of behaviour. This is described by Piron through three criteria: the purchase must be completely unplanned, some kind of stimuli must trigger the buying process and the decision is made on the spot spontaneously. According to the involvement in the purchase and the number of differences between brands, there are four types of consumer behaviour types: complex buying behaviour, variety-seeking behaviour, dissonance reducing buying behaviour, and habitual buying behaviour. Factors influencing the purchase are split into two groups: internal and external. Internal factors influencing these purchases are age, sex, education level, and income while external factors are stimuli used by brands like the quality of the service, cosy atmosphere, vibrant colors, smells and many other marketing tricks used like sales promotions. Some of the most used sales promotions are loyalty programs, price discounts, free samples and buy one-get one promotions. When engaging in this process, a consumer doesnt use his rational brain and becomes an impulsive buyer easier.