Water can also penetrate where the fabric joins, and seams and zips are both key areas where this can happen. Most jackets at this price point are likely to be sewn and then backed with a waterproof tape that’s glued over  to provide waterproofing; these are commonly referred to as ‘taped seams’.
A more water-resistant, though pricier, process is laser-cut and sealed seams, where they are bonded together.
At the budget price point, waterproof zips are uncommon, but for short-to-medium trail rides in moderate conditions, this shouldn’t be a deal-breaker. Instead, at this level most jackets will opt for a storm flap, which is an additional layer of waterproof fabric that sits over and covers the zip while riding.