I can only think of one reason why some of the MPs are making such a meal of brexit, and that's because they want to stay in and commit the UK to lagging behind under the deadweight of EU membership.
The argument that imports will cost more rests upon the assumption that the EU countries will put big tariffs on their imports from UK, fair enough but we can do the same and we import more than them, so we'll be winners and the extra revenue can be used, that's if the government of whatever party doesn't hang on to it, for subsidising imports with a bit left over for general funds.
As for jobs, because we'll be able to make things cheaper, we'll sell more so more people will be needed, those in non-manufacturing jobs will not be affected. There may be a need for more home production meaning even more jobs and reduced deficit. For people who want the UK to be better for our children and descendants, no deal is the best to go for. Also leaving with no deal will save us £39 billion at least and roughly £16 million a week, that's not a bad start to our journey back to better things.