The Nifty 50 Trolley is a tourist trolley that takes riders about South Lake Tahoe. The trolley runs to each stop on the route every 60 minutes and only costs $3 for the day! On Route A the day lasts from 10:30am to 8:30pm on the main route ... and from 11am to 6:30pm for route E (which BTW takes you to the Emerald Bay parking area).
BlueGo also offers door to door services from other properties to the casinos AND cheap wifi in select locations about town!
So if you are spending time in South Lake Tahoe/Stateline and didn't rent a car .... check these folks out ;)
RNO is the international airport closest to South Lake Tahoe and Stateline. I researched the shuttles, as I didn't need a car once I got there ... but it was GETTING there that I worried about. It turns out I didn't need the shuttle info I found, but I might next time, so here's the link to the airport website on transportation options.
We ended up sharing a rental car. It was cheaper for 4 of us than using the shutlles. South Lake Tahoe is about an hour to an hour and a half drive from RNO, longer if a shuttle is used d/t stops along the way.
Some folks came in from Sacramento Airport .. which is about 100 miles away. But they don't have shuttles to the Lake Tahoe region. So I'd only recommend Sacramento if you plan on renting a car or have other fun stuff planned in the area :)