The scooter can weigh as little as 200 lbs or as much as 350 depending on size and model.
If you are both small to average sized folks, you can get little 50cc models from any number of manufacturers that will weigh 200 or less and carry one person at about 25 to 40 mph on level ground.
A step up would be a 125cc about 50 lbs heavier, will carry will carry 2 small to average sized folks at up to 40 or so, a single person up to 55 or so.
Bigger 300cc and up are basically Motorcycle sized and water cooled, 350 lbs and up.
A honda ruckus type (minibike look) will be about 60" long, others closer to 66-70"
Honda, Suzuki, Vespa, Original scooter, Yamaha are the premium brands.
Kymco, SYM, and Lance are one step down. And the Chinese clones follow the pack.
Prices range from $700 or so for chinese, to $1800 for the mid grades, and $2500 and up for the premium.