If you're talking about the install cost, then it depends. If you're using the same amperage circuit, then the difference is pretty minimal, just the work of having to actually mount the wall connector on the wall. The wall connector can even be cheaper to install since it only needs three wires where a 14-50 needs four. If the wall connector is installed with a bigger circuit, then you've got more expensive wire (how much more depends on distance and how big a circuit) and in extreme cases, panel upgrades and the like. If you have questions about a quote, always get them to itemize.
Now, the common wisdom here about Tesla installs is that they work off a quote sheet that lumps installs into categories like 0-25ft, 25-50ft, etc... Some folks who have difficult installs and/or are near the upper range of a category have reported that the Tesla quote was very competitive. People who had easier installs found them expensive in comparison. People also seem very happy with the quality of the Tesla installs.