Pots & saucers are sold separately & size match as follows:
5.3" pot - 4.3" saucer (waterproof lined)
6.2" pot - 5" clay saucer
6.75" azalea pot - 6" clay saucer (Same set as one of the available kits.)
7.9" pot - 6" clay saucer
 
Lined saucers can be painted on the outside but not the inside.
 
You will very likely have enough paint leftover from your Paint & Plant Kit to decorate another pot or two or three, depending on the size. So, you may want to add a few pots in your cart, just in case.