I sent a bottle of wine from Portugal to Connecticut, USA. This is a gift for my friend. The bottle is 0.75L and costs about 130 euros (about $140).
Will my friend pay a tax upon receiving the gift?
There will not be a gift tax. In the United States somebody that receives a gift doesn't pay a tax.
Each state in the US regulates alcohol. That means the state determines if alcohol can be sent from their state, sent to their state, or sent within their state. The carrier (US post office, Federal Express, United Parcel Service...) may also have their own policies regarding sending alcohol.
So if you are sending the wine from Portugal to Connecticut you need to make sure that it is legal to do so. If you are ordering the wine from a store within Connecticut, they are aware of the laws. If you are ordering the wine from someplace else in the US, they should be aware of the regulations that apply to their state and also Connecticut laws.