Under $1000 - lots of reliability and quality risks, and usually non name brand battery, and even non name brand brakes or other important components. Usually only buy on line.
Under $1500 - usually fair quality hub drives and sometimes some name brand ebikes. Components ok for recreational riding. Maybe not so much for commuting or more avid cyclists. Would not expect a suspension fork on these models but if there is, it's quality and the other components won't be as good, since a good quality name brand suspension is well over $250 retail
Under $2000- this is where you will see better derailluers, smoother shifting, more likely hydraulic brakes, better than average size battery (I.e. if 48 volt, then usually at least 13 ah capacity), integrated front and rear lights, name brand Samsung or Panasonic cells, likely a suspension fork if you are seeking an ebike with it, better quality tires, fenders and rear rack. Occasionally torque sensing feature on hub drive models.
$2000 - $3500 this is where you start to see mid drive offerings, as mid drives cost more to manufacturer as do the frames that need to be redesigned to handle them. You will also start to see batteries that are more integrated or concealed better in the frame, maybe color displays, more frame colors from more brands and the choices increase dramatically for frame geometries and even some cool software options, like blue tooth, allowing for more detailed apps or gps location benefits.
Above $4000 - now the sky is the limit on price and really high end features and start seeing carbon frames. Its the wild west and too hard to categorize but opens the door to even more vendors to choose from (or be confused by)