What dose "tacks" mean?
In New York City, which tacks $1.50 on top of the state tax, the high school smoking rate is 8.5%.

If you tack something to a surface, you pin it there with tacks or drawing pins.

In New york city, if i buy cigarettes, I pay $1.5 plus the state tax plus cigarette's price. Is it right?

Question

What dose "tacks" mean?
In New York City, which tacks $1.50 on top of the state tax, the high school smoking rate is 8.5%.

If you tack something to a surface, you pin it there with tacks or drawing pins.

In New york city, if i buy cigarettes, I pay $1.5 plus the state tax plus cigarette's price. Is it right?

Answer

Absolutely correct, to "tack on" is a phrasal verb, and means to add something.

In this sentence, they could have also said, "In New York city they tack on an extra $1.50"

Answer

Correct, Terry. Tacks = added too