The donor is generally responsible for paying gift tax. The general rule is that any gift is taxable gift. However, there is annual exclusion for each calendar year. IRS announced 2016 Estate and Gift tax exemption.
"It's official-for 2016, the estate and gift tax exemption is $5.45 million per individual, up from $5.43 million in 2015. That means an individual can leave $5.45 million to heirs and pay no federal estate or gift tax."
See an article in Forbes http://www.forbes.com/sites/ashleaebeling/2015/10/22/irs-announces-2016-estate-and-gift-tax-limits-the-10-9-million-tax-break/