I have! In general, I try to avoid ever buying things, but if I've enjoyed a game for a few days, I try and spend at $5 - $10 to show my appreciation, so I did buy the two packs on sale. (.99 and 4.99)
I actually wanted to post a thing today that I really really admire this shop system!! If anyone hasn't looked at it yet, there is a limit on how many diamonds you can buy. In addition to that, after getting 2,500 exchange tickets, you can get a diamond miner that gives you 100 diamonds a day. It doesn't break.
Basically, if you pay a normal full price on this game, you're done. It won't ask you to suck more of your money forever, and won't even let you use more than $80, won't make it frustrating without the items, and will give you a constant supply of diamonds once you're done. I think that's extremely responsible, in general, and specifically because it's a game marketed toward children. I've seen games for kids that you can buy a $99 pack and still blow through it's items in a few days, and those items are random chance items so you might STILL not get what you want.
If I keep playing this game for at least a month, I'm going to buy enough to get the diamond miner just on principle supporting of this responsible approach to in-app transactions.