1. What type of used or second ramps are available
2. How and where will you be using the ramp
3. Size and shape of the ramp
4. Operating the ramp safely

After decidng what the correct used wheelchair ramp is you can safely look online.

Factors to Consider When Purchasing a Used Wheelchair Ramp:

1. Where will the used wheelchair ramp be located? Generally ramps are used to climb up curbs, enter a doorway or a step or even loading and unloading out of a van. If your ramp is located at a public entrance you will need consider other users to the building, so its recommended not to use a portable ramp. If you need to carry around your used wheelchair ramp you need to consider the weight, look for a lightweight compact ramp.
2. Where will you store the wheelchair ramp? Decide where to store the wheelchair ramp when it’s not in use. Some designs of ramps can be stored in the trunk of the car. The size of your storage  area will determine what ramp you wil buy.
3. What type of ramp will suit your needs? Do you want a permanent or portable used ramp.
4. What is the weight capacity of the ramp? What type of length and height do you need?
5. Do you need a non-slip surface on the ramp?
6. Finally, what pric are you willing to pay for a used wheelchair ramp?