Emulsion Paint, esp Blue, Green, Yellow (March PE15)

I'm seeking odd tins of paint, (emulsion not oil-based please), mainly basic colours - bright Blue, or bright Yellow, or deep Green. Also black, a little red, maybe brown,.. They can be small amounts, used tins. I want to mix them to make a countryside-view mural painting on my boring bottom fence. (I have plenty of light green!)