Ok, Let's replace your example with the word, Car.

I saw some people buy a Car for 2000$ just a month a ago.

Now I can buy a Car for only 500$, it is cheap!!

Same thing, right... You could have bought shit for whatever reason, but you still paid $1500 less for it, than what you would have paid a month before. 

Now take fiat currencies

I saw some people buying 2 bottles of Coca-Cola and one box of Kentucky fried chicken and 10 chocolate bars for $10 in 2015.

Now in 2018, I can only buy 1 bar of chocolate and 1 bottle of Coca-Cola with $10, f@#$%n!