Help with wife's holiday gift--graduated neutral density filters and inexpensive IR filter for a D3100!

I was wondering if anyone could recommend an inexpensive set of graduated neutral density filters for a Nikon D3100? My wife is a photography enthusiast and I'd like to get her some for the holidays. In addition, I'd like to get a visible light blocking IR filter as well. Let me know if you have any opinions on the matter or good resources!