Bulk Barn has colored 4lbs fondant on sale. White is not on sale but ivory is. Can I get ivory fondant and color it with any color I like? I'm not baking anything at the moment but wanted to buy and keep for a future cake.
Yes . . . although it will be hard to get dark colors without breaking down the fondant from so much color kneaded in.
Since you're not starting with a white base, your colors will probably be a little off. For example, mixing in blue coloring will probably give the fondant a green tint.
I usually make my own mmf but for a wedding cake I did, I ordered 20lbs of ivory. I had some left over so I used it to make decorations for other cakes. I was able to get some nice colors, but they weren't the same shades as when I started with white fondant.
If you need something exact, try kneading in some white gel paste (titanium dioxide) to whiten it, let it rest as long as possible, and then add the color.