Reddit mentions of Speedball Underglaze Studio #1 2-Ounce Bottles, 12-Pack

You need to buy glazes, which depending on how much variation you want is probably going to cost you anywhere from 10-20 dollars a per color if you want the expensive stuff, however you can probably buy a set of 12 underglazes for about 47 dollars and a pint of clear glaze for about 10.

If you go this way, it's pretty similar to painting regularly, all you have to do is slap a few coats of clear glaze on it after you have the design on it and find a ceramics studio that will fire it, the place where I live charges about 2 dollars a pound for each peice or about 60 dollars to rent an entire kiln.

Here's some underglaze sets and a clear glaZe you could use, but you should check the nearest studio to see if they have any discount glazes
http://www.amazon.com/gp/aw/d/B0044SATSM/ref=mp_s_a_1_2?qid=1415905256&sr=8-2&pi=AC_SX200_QL40

http://www.amazon.com/gp/aw/d/B003IGIDR0/ref=mp_s_a_1_1?qid=1415905406&sr=8-1&pi=AC_SX200_QL40

http://www.amazon.com/gp/aw/d/B0044S97QW/ref=mp_s_a_1_6?qid=1415905420&sr=8-6&pi=AC_SX110_SY165_QL70