Well,

I picked up some Transformers at a Garage Sale. Now I've got some questions. The first one is:

I've got two Optimus Prime trailers. One has purple insides and the other has blue. What's the difference?

LMK,

Thanks,
etmartin

are the trailers gray or black?

They are Black...one has blue immobilizers on the bottom, the other has purple...they match the insides.

Thanks,
etmartin

you got both variations of a G2 prime trailer there:

you can read more about them here:
http://www.geocities.com/futuristgroup/vprime.html