Economy part 2

Next question is this:
Will there be a supply and demand market? If you buy a baker's whole stock of cakes bar one, does his price go up? Can you then sell those bought cakes back to him for a profit and make the price drop again? And then buy them again? And...?

I do feel that there will be a supply and demand market, but I hope to leave NPCs out of this altogether.  All players able to enter the field will be able to clone the blocks into their backpacks, meaning that the majority of blocks will have little to no worth unless someone is simply unwilling to go out into the field and yet still wants basic blocks.  The main area where I anticipate shortages will be the critical materials of metal and energy crystals.  I feel that there will be many levels of quality in each of these types of collectibles, and since they will be the primary materials for use in anything crafted demand for them will be a given.  Since venturing out for these things is going to be difficult and dangerous it will encourage teamwork.  At the same I don't think that any one player will be able to create a monopoly or corner the market on any of these materials as any player, utilizing a builder, able to make it to these resources and back to the base will be able to sell them.  Players playing other classes will be encouraged to escort the builders by virtue of the fact that the builder will be able to trade the materials they collect with them as payment.  This will still be a risky venture as enemy players I'm sure will patrol looking for easy targets that they can freeze and hope they teleport back to base, leaving whatever materials they have collected for their plunder.  As with any free market there will be people who will make a lot of money from those who sell too low as this is a common mistake new players and unobservant players will tend to make.  With this type of economy players will easily create their own missions for material gain and will generate continued interest in playing.