Well, for some people it's just an inconvenience to drive all the way out to the valley, especially considering weather conditions, personal obligations, or other reasons. Gas isn't the only issue, and it's not like anyone doesn't want you to come, it's just not always possible for someone to fit it in with their schedule.
Maybe you could look into the bus schedule? It'd be a lot cheaper, $1 for each way. I'm not sure how the valley bus runs, but I'm sure its manageable.
http://www.spokanetransit.com/ridesta/routesschedules.asp for more info. The Cheney bus is route 65 and 66. 66 is the faster bus to get to downtown Spokane, it just goes straight from the PUB to the bus plaza in Spokane. However the 65 just runs all around Cheney, so it's like an extra 15 minutes longer of a ride if you decide to take that one.
I believe the bus leaves the pub every 5 or 7 minutes after the hour, so it probably leaves from Spokane to Cheney at every 30 minutes after the hour, give or take a few minutes.
Look into it, in case no one is able to give you a ride in the future. It would be nice if you were able to make it to more of these tournaments. Considering you do get better each time you attend the tournaments, it would be interesting to see how your skills may improve over time.