I literally just had an electrician came out to do the wall charger install, he ran a 20 foot conduit but it's not as bad as your situation. He charged me $600 for the install, $100 to pull the permit. So that should give you an idea of the going rate, but 100 foot is at a whole another level. $800 doesn't sound too bad depends on how much he's going to charge you for the 14-50, maybe $1000. One thing to note is there're federal and local rebates for wall chargers but not for NEMA 14-50. So theoretically, if all my rebates came in I get the wall charger literally free, just paying for labor. Just a thought for you. But NEMA 14-50 like previous poster said is what you should get at minimum unless you're stuck with the current situation. I called at least 5 different electricians and some of them are crazy high, like $1500-$2000 just for the install, so don't accept the first quote definitely do some comparison and check their reviews. Most electricians just require to see your power panel, distance, picture of the potential conduit run, and then final location of the plug/charger, they don't even need to come to your house so it's super easy to get quotes. I know some people are also against permit, but that's a personal thing. I feel safer knowing I got a permit and if something happens insurance can't deny my claim, that's the only reason why I wanted them to pull the permit to ensure it's 100%. One more plug for the wall charger, if you are planning to get another Tesla down the line, a single 60amp circuit can support multiple Tesla Wall Chargers supposedly according to the manual.