To go back to a favorite topic of mine, let's talk about what the implied freight rate says about your setting. Hopefully by putting something that feels abstract and not particularly meaningful in very concrete terms this post can provide a good framework for thinking about how your setting works. It definitely informs what is and isn't being shipped.
Before we begin, a note about assumptions -- a Mothership credit is worth between $1 and $5 depending on a lot of things. As in my previous posts on starship economics, I've settled on about $4 per credit based on a basket of PSG and APOF items and services that aren't likely to change much in value in a retrofuture setting. Other baskets may get a lower value. So there's a bit of an error bar when you connect this stuff to the numbers in the PSG. Relatedly, I assume (with a very strong basis) that shipping costs roughly reflect energy costs. The ability to light a fusion torch implies other things about the economy (like how expensive fuel is). Whatever number you pick has implications elsewhere.
Also, remember that your freight rates are only a potion of whatever something costs. The size of that portion is extremely variable and rests on a lot of boring economics but the short answer is that if it's cheaper to pay exorbitant shipping rates than set up a widget factory at the destination the widget will be shipped. Colonial economies probably have some really bizarre price distortions as a result. For example, if shipping costs are high and substantially exceed other costs you won't see much difference between luxury foods and regular imported foods (anyone who can afford not to eat locally produced algae glop will be eating lobster, caviar, and fancy steaks).
And now, examples: