The best affordable mounts can hold an average-size laptop (13 - 17 inches), allow adjustments to a comfortable working position, and are designed so that you can easily install yourself without modifying your car’s interior. Except the portable RAM Seat-Mate, most other mounts are secured by the passenger seat’s front mounting bolts. You should also keep in mind that the strength of a mount’s base plate, which attaches to the seat bolt, determines how stable the mount is.

Inexpensive plastic shelves you can hook over a steering wheel or front seatback are not meant for regular use.

The best affordable laptop car mount: RAM No-Drill Laptop Mount (more stable and easiet to adjust than all other options)
The second best affordable laptop car mount: Bracketron Universal Vehicle Laptop Mount
The third best affordable laptop car mount: RAM Seat-Mate (lightweight, portable, so you can remove and use in oother vehicles)