Journey Tokyo or Kyoto to Sapporo

I will need to get to Sapporo on the 13th March from either Tokyo or Kyoto by the cheapest possible means but not take too long to get there. I need to return to Tokyo on 21/22nd. Can you tell me the best possible options? I've looked at Skymark flights but they are coming out at 320 english pounds return. any advice welcome

The options are outlined here:
http://www.japan-guide.com/e/e5306.html

I will need to get to Sapporo on the 13th March from either Tokyo or Kyoto by the cheapest possible means but not take too long to get there. I need to return to Tokyo on 21/22nd. Can you tell me the best possible options? I've looked at Skymark flights but they are coming out at 320 english pounds return. any advice welcome

320 quids for return is incredible. I checked their online quotations on your requested dates.

13th March Tokyo-Sapporo: 10,300 to 11,800 yen (Maewari 21 fare)

21th march Sapporo-Tokyo: 12,800 to 15,000yen (Maewari 10 fare)

It works out from around 110 quids for return.
Beware of the fares' regulations.

http://www.skymark.co.jp/en/index.html