travel from chicago to buffalo

travel from chicago to buffalo?
My friend and I wanted to travel from chicago to buffalo in May and return before June 1st. I wanted to know what is the cheapest way to travel. I tried checking flights. The cheapest is Southwest airlines. Is there any flight cheaper than that? Also the amtrak has no rooms available on the day I want to go. Is there any other train that goes?
Other - United States - 3 Answers
Random Answers, Critics, Comments, Opinions :
1 :
check bus lines for lower costs.
2 :
Megabus (megabus.com) will get you from Chicago to Cleveland fairly cheap (I priced $33.00 one way on May 6). But they do not go through to Buffalo - maybe you can take Greyhound for the final bit. Return travel might even be cheaper - the first tickets they sell on any route are $1.00, but it creeps up from there.
3 :
Amtrak is the only national passenger rail in the US. For airfares, try www.kayak.com -- they have some cheaper flights than Southwest.