Taking Amtrak from SF to Truckee would probably be the cheapest and easiest. You could also fly, as someone suggested, but SF to Reno isn t as traveled as, say, SF to LA or Las Vegas, so it s actually not that cheap (the cheapest fare, if you book far in advance, is just under $100. If you don t book far in advance, you ll be paying over $200). It would be a lot quicker though... if that s an issue. I wouldn t rent a car as they tend to charge a lot to drop it off somewhere other than where you picked it up.But if you re just going for the most economical option... Amtrak. $42.
I would rent a car, unless you can find a Reno/Tahoe Casino Tour bus that you can get onto in SF the day you will be there. Usually these are subsidized by the casinos and are cheap, cheap, cheap! No one says you have to use the return ticket (oe even gamble)! Look at the SF Chronicle Newspaper website for these buses or do a web search. Southwest Airlines also does low price flights between SF and Reno.
cacth bart or bus depending on your funds and transportation that s your best bet
Hitchhike