For our Grimdark Future game in June, I needed a dropship model as the centrepiece/objective marker for the table. Since none of us had one at hand, I decided to search my neighbourhood stores for a toy that could be easily converted to look "sci-fi". What I found was this attack helicopter that cost US$9.
The thing that made the model convincing for me were the while decals FG passed me. I am going to replace the guns on the wings with 3D-printed lascannons to make it look more 40K, but this was how the model looked for our game.
I had fun painting the model, so much so that I have now ordered a Hasegawa Egg Plane model to be converted into an Ork Dakkajet.