The primary metal detectors may be not very expensive, but you can still find many coins, relics and other treasures just like the higher priced professional metal detectors. Although it may have a few defects, I think you can overcome it easily after some practice.
Most primary metal detectors are lighter than the professionals, so it will be comfortable for you to swing longer, that means you can spend more time metal detecting and you may find more treasures.
Last but not least, the primary metal detectors are much cheaper, so it gonna save money for you. And what if you couldn’t fall in love with metal detecting, the primary won’t waste you much, right?