Here are some gas stations we use for our trip to and from Tahoe. We haven't researched around much, but we found these stations to have fairly consistent low prices. They are all literally right off the I-80 freeway. Safeway gives 3 cents discount per gallon for their club card members, but sometimes other stations are still on par or cheaper even with the discount, so check around.
We welcome other suggestions on gas stations to add to this map. Just let us know