UFO Defence

Free Manufacturing.
Go into the manufacturing screen and pick the item you want to build, but leave the number of engineers and the quantity at 0. then hit OK and go back to the main base screen. Now, go back into the manufacturing screen and select the item that you just set up to build. now put all of your engineers on it and set the quantity as 1. this should build your item without using money or supplies(i.e. ellurium). its slow but it helps when it comes to building expensive items which you can sell for pure profit.