We have a fridge box DPOR with full length pantry drawer. Love it! best thing we added to our camper, space for everything and no need to rummage around in plastic containers like we did when tent camping.
I think it is cheap for what it is, but it is still alot of money.
We werent interested in trying to build our own, we didnt have all the required tools and while we have know how it would still have been a bit of trial and error which would have taken longer and probably required us to buy extra material to replace the pieces we made mistakes on. All though we did not add up the difference I am not sure it would have been worth our while once we factored tools, time, stress, materials..... replacement materials!
The added benefit of not making it is that we supported a company that is unique in the camping scene.
Our camper has no lip near the door.