In order to get this, you need to reach level 5 in Ghost Mode, Ghose Sense and Undead Rush. You do NOT need to level up Lucky Horseshoe. That being said, it still doesn't look pretty.
(Some have said they needed Horseshoe for another achievement. I had level 4 in Horseshoe when it popped, but I didnt need 5 in that whereas I needed 5 in the rest. So I'm assuming Horseshoe is irrelevant.)
You'll notice that the level 4 prices are wonky compared with the level 5 prices. Those are in the game. I don't know if that's a developer error or what, but level 5 is much cheaper than 4.
I don't have the costs for each level (since I already went through), so if anyone can help with the missing ones, I'd appreciate it. :-)
Level 1: 1000 gold/1 diamond
Level 2: 8000 gold/8 diamonds
Level 3: 40,000 gold/40 diamonds
Level 4: 250,000 gold (!!!)/250 diamonds
Level 5: 25,000/1000 diamonds
Level 1: 2000 gold/2 diamond
Level 2: 10,000 gold/10 diamonds
Level 3: 70,000 gold/70 diamonds
Level 4: 30,000 gold/300 diamonds - This has fluctuated
Level 5: 35,000 gold/1200 diamonds
Level 1: 3000 gold/3 diamond
Level 2: 15,000 gold/15 diamonds
Level 3: 100,000 gold/100 diamonds
Level 4: 400,000 gold (!!!)/400 diamonds
Level 5: 50,000 gold/1500 diamonds
Since the level 4 prices are so far out of whack, it's pretty much a given that you're going to have to spend some cash to get past that. $20 will get you 2500 diamonds, which might also help buy extra lives for Endless Runs. Also, if you're going to spend cash, $5 will get you the double gold perk, which will help a lot with the Gold Fever achievement and help you finish this faster.
Best of luck!
Edit: Thanks to Bryan2041, UnrealKarnage76 and Mjolnir 69 for updating the prices!