Data plotting software

I have a bunch of data that I need to plot, and in my innocence, I thought Excel would be able to handle it. It’s a 3D plot, which apparently Excel doesn’t do without much jiggery-pokery which I’m frankly not interested in. Fairly simple - 2 parameters on the X and Y axes, and the values on the Z axis, all of which are in a comma-delimited text file.

Does anyone have any suggestions for freeware or shareware that I could use for this? I don’t really want to pay $100 for a plotter that’s just going to be used a few times. I figured that as we have many scientific-type people here, it would be worth asking.

gnuplot does things like that.