Are there 3d printers at an affordable level that print several materials such as metal, plastic, etc? Do any printers mix materials or they solely dedicated to one material?


What about typical printing sizes? Are they all different or is there size classes? Personally I would need about 15" x 15".
These are the machines I am looking at let me know what you all recommend (Any cubic mega zero 2.0, SainSmart coreception COreXY, Ender 5 plus, Ender 3 Pro, Ultimaker S5 Plus)


ALso What is a slicer exactly? I will understand more when I actually get my printer but it sounds like they come with software that you build models in .stl format. Then you must take these files and convert to GCode that your actual printer reads? Is this correct?