There is no one “best” machine. If you want a touchless wash, a lot of people like
Washworld, Petit,
PDQ, Water Wizard, etc. if you want friction, a lot of people like Istobal,
Washworld, Ryko, Autec etc. When you buy a wash you have to find a distributor that is close by that will give you good support.
I’m not criticizing you or in any way or demeaning you or your question, but asking “what is the best and cheapest machine “ on this forum indicates that you do not have a lot of knowledge or experience with car washing - and that is fine. But that is why you need to find a very good distributor close to wherever you are. Good luck.