At the end of April 2017 there is a May Day (Lucky) Draw that allows you to get some free goodies.
Next to the icon for the sales at the right top of the screen, there is a new icon for the Lucky Draw. When you click on it, there are three Steps to select possible prizes and afterwards you can make draws from the prizes. This works in a similar way as the Tarot Reading, and the same as the New Year Draw and Carnival Draw. However the first lucky draw already costs 7 Golden Hourglasses, the second 12 Golden Hourglasses and afterwards it costs an increasing amount of Golden Hourglasses to make more selections. These Golden Hourglasses can be acquired by completing the Daily Rewards (2 Golden Hourglasses per day) to a certain level (do not forget to claim them each day) and by topping up a minimum of 1000 gold in the gold store (5 Golden Hourglasses).
You have to pick 4 prizes from Step 1. The prizes are an 300 Gold, 35 Mini Material Chests, 20 Intensity Crystals (I), 2 Sentinel Gem (I), 2 Stallion Stone (I), 2 Air Stone (I), 20 Intensity Crystal (II), 6 Refining Stone (I), 10 Intensity Crystal (III).
You have to pick 3 prizes from Step 2. The prizes are 10,000 Gold, 135 2000 Hero EXP items, Sir Gawain, 7 Refining Stone (II), Sir Bedivere, Sentinel Jewel (II), 5 Intensity Crystal (IV), Stallion Gem (II), Air Gem (II).
You have to pick 2 prizes from Step 3. The prizes are Champion Gem (III), 40,000 Gold, Champion Jewel (III), 7 Refining Stone (III), 5 Intensity Crystal (IV), 2 Warmonger Helmet Scroll Fragment, 4 Warmonger Necklace Scroll Fragment, 30 Noble Badges, 3 Warmonger Armor Scroll Fragment.
It is difficult to say what the best prizes are. Not all of them have a direct monetary value, as you cannot purchase them with gold. I went for Intensity Crystals and material chests from Step 1, gold and heroes from step 2, and gold and noble badges from step 3.
Once you selected the prizes you can Confirm your pick (if you don't, all will be reset the next time you enter the May Day Draw). Once you have done that you cannot change.
The prizes are nice, but you need to spend to get more than one prize. Like with other seemingly random things in the game, they are not very random at all. I expect it is impossible to get the top prizes in your first draw.