I need to choose PIC MCU for a project. My priority is the dimensions and the price. PRice should be at most 4$ and the dimensions at most 6x4 cm. does anyone can suggest me anything?
No one can recommend a chip based on such limited information. I would expect you to have some requirements for I/O, ADC maybe, supply voltage, SPI, UART or something. Not just cost and size. Try the interactive selection guides on Microchip's web site.