Kansai Airport to Tokyo

Hi there,
I first traveled to Japan - Osaka & Kyoto last Nov 2012 and got addicted to Japan instantly. I plan to return in mid June this year and Tokyo will be my next destination. Need some advice, 1)how do I get to Tokyo from Kansai Airport? I intend to take the Shinkasen to Tokyo.
2)How and where do I take the Shinkasen to Tokyo
3)What is the best and affordable option on purchasing of tickets?

how do I get to Tokyo from Kansai Airport?

There are many different options. One is to fly there. JAL, ANA and Starflyer fly into Haneda Airport. Jetstar into Narita Airport.

How to get from Haneda Airport to Tokyo:
http://www.japan-guide.com/e/e2430.html

And from Narita:
http://www.japan-guide.com/e/e2027.html

Alternatively, take a train or bus into Osaka and a train or bus from there to Tokyo.

How to get from the airport to central Osaka:
http://www.japan-guide.com/e/e2033.html

How to get from Osaka to Tokyo:
http://www.japan-guide.com/e/e4006.html

I intend to take the Shinkasen to Tokyo.

In that case, take the Haruka limited express and Tokaido Shinkansen via Shin-Osaka Station. You can buy the ticket for the entire trip at Kansai Airport:
http://www.hyperdia.com/

What is the best and affordable option on purchasing of tickets?

There are no considerable discounts for shinkansen travel. For more affordable options, you should consider flying or taking the overnight bus.