In orthodontics, aligned teeth is second nature. It's primary purpose is for medical reasons, to correct the bite for efficient mastication without injuring the jaw, to provide ample space and exposure for easier cleaning to prevent cavities, gingivitis and other more severe health issues. For people who have straight teeth only on one arch and wishes to correct the other arch, it is possible to just put braces and correct it independently but this is only possible after a case by case review and assessment to ensure that the bite will be or remain correct.
It is always a good idea to get second and third opinions to help you make the best decision. I advise against deciding based solely on price because it is not the basis of experience, technique and quality of care. As a reminder, it is a good idea to ask questions while at the dentist but make sure you ask what you need to know and not a condensed lesson on dentistry where doctors paid years of schooling to learn.