Elecrow provides high quality assembly service. We can solder the most common used package such as 0201/0402/0603/QFP/QFN/BGA/THT. We do not have any minimum quantity limitations. You can make the very first 1 pcs prototyping PCBA, or make thousands for your mass production. As the customer requirements, we can solder the PCBA with hand or with reflow oven. For quantity>50 pcs, we will use the pick-and-place machine to place the components. Besides, lead free soldering available for the ROHS compatible. Part mapping file maybe needed for the components placement with pick-and-place machine. As the cost, the soldering cost will depend on the quantity of Pads, 0.03$ for SMD Pads(with stencil) and 0.04$ for THT pads, with discounts based on the quantity; for prototyping round less than 20 pcs, 5$ will be added for each design.