Biosimilars are cheaper than original drugs and are thus of interest to the public. The aim of this article is to assess the benefits of introducing more than one biosimilar for the same substance (active pharmaceutical ingredient, API). The hypothesis is that the introduction of successive biosimilars of a specific original drug reduces the price of the selected API. The study focuses on drug prices varying with the successive arrival of new biosimilars. Three drugs that have at least three reimbursed biosimilars on the market were selected, two from the same therapeutic group (adalimumab and infliximab) and one (trastuzumab) representing another class of drugs. The following data were analyzed: price variation after the introduction of the first, second, and third biosimilar, and the average price reduction for all three biosimilars. Additionally, a literature review was conducted. The reimbursement of each new biosimilar is beneficial since it is associated with a price reduction in percentage terms. However, the first biosimilar brought about the greatest savings due to the higher initial prices of the original drugs and to Polish reimbursement rules. This article is helpful for when taking healthcare decisions regarding the pricing of and reimbursement for new biosimilars.