We need to run new wire from pole to mobile home. Was told 4 o 2 o would be the best , just would like an idea of cost just for the wire.

You need AL 4/0, 4/0, 4/0, 2/0 URD quad, or separate conductors of 4/0, 4/0, 2/0, #4. Copper sizes will be smaller but more expensive.

I have no idea on price for 200A quad cable right now. I know 3 wire URD is around $2/ft.

Are you going just by what you are told, or do you know what you need and what you need to do?
IMO this is not really a DIY kind of job.