PS-- Once you have enough coins to play with, buy Bronze and then buy Silver. I have millions having never spent a dime and never buying (with coins) any of the expensive packs. Those cheap ones have better ROI and still good pulls.
For example, I just opened 5 Silver (went to Silver from Bronze now that I have enough coins that I'll retire the game with a ton of unused coins) and pulled 2 88 Diamond. Spent the price of 1 Gold Plus and got back like 250k. While a little luckier in few packs than usual, 40% of my packs were good instead of depending on only 1 pack. From Bronze, I've pulled multiple 300k+ cards and a ton of Gold collectibles and other semi-valuable golds (30k and up). That's where my stack came from primarily. Now I'm set and more. Of course, others have more than me having also never spent anything. My case is not unique. Do that.