1. Cuba has two currencies.
There’s the Cuban peso (CUP, otherwise known as the national coin), and the convertible peso (CUC), which is equivalent to 25 CUP and on par with the USD. Basically, tourists have a separate currency from locals and yes, it is confusing.
2. Because of that, it’s not as cheap as you’d think.
Since tourists have their own currency, prices can be raised to meet foreigners’ buying power. For example, a museum entrance can cost 8x more for a visitor than for a local. Relatively speaking, Cuba is still affordable, but expect to pay significantly more than Cubans.