Place Buy Orders

Excellent idea!

Obviously, sell orders would be an great addition to this. (selling x amount of resource when the market price reaches y Dust).

Another really nice feature I'd like to see in the game is a multi-turn transaction with the market (buy x Dustidious Trees per turn for y turns). A benefit that I see using multi-turn transactions is fighting inflation of market prices for resources that you plan on buying a lot of.

If the market history shows that you tend to be the only faction buying Dustidious Trees, then buying smaller amounts per turn can stave off large price spikes that occur when you buy in bulk. So if you don't have a pressing need on this turn to buy a large amount of a resource, but know that you will need some later, buying small amounts every turn can keep the overall costs lower especially if someone else sells what your buying during your multi-turn transaction.

I think this would be an excellent addition for both Legend and Space 2, honestly. The market is a great way to use some cash to balance out some resources you're struggling with, so a couple additions to use it a little more effectively would really help utilise it to your best advantage.

And as BeatYourHeadIn suggested, some Buy Over X Turn systems would make it a lot more robust, on top!