The pricing of single-sided FR4 (Flame Retardant 4) printed circuit boards is influenced by several factors, making it a dynamic aspect of PCB manufacturing. FR4 is one of the most commonly used materials for PCBs due to its good electrical insulation properties, mechanical strength, and flame retardant characteristics.

　　The size of the single-sided FR4 PCB is a primary determinant of its cost. Larger boards require more raw materials, including the FR4 substrate, copper foil, and solder mask. Additionally, the manufacturing process for larger boards may take longer, increasing labor and production costs. As a result, smaller single-sided FR4 PCBs are generally more affordable, making them a popular choice for simple electronic devices and prototypes.

　　The thickness of the FR4 substrate also impacts the price. Thicker substrates are more expensive because they require more material and may involve additional processing steps during manufacturing. However, thicker substrates offer better mechanical support, which is necessary for applications where the PCB may be subject to physical stress or bending.

　　The complexity of the PCB design, such as the number of holes, vias (even in single-sided boards, there may be some through-holes for component mounting), and the density of the copper traces, can affect the price. Boards with a higher number of holes or more intricate trace patterns require more precise manufacturing processes, increasing production costs. Moreover, special requirements, such as a specific surface finish (e.g., HASL, ENIG), can also add to the overall cost.

　　The quantity of PCBs ordered plays a significant role in pricing. Manufacturers often offer volume discounts, meaning that the unit price of single-sided FR4 PCBs decreases as the order quantity increases. For small-scale projects or prototyping, the per-unit cost may be relatively high, but for mass production, economies of scale can significantly reduce the cost per board. Additionally, the location of the manufacturer and market demand can also influence the pricing of single-sided FR4 PCBs.