carbon credit: EU law fines ICE car makers for making cars. they inturn purchase carbon credits to have the right to keep polluting. further more tesla made 53 B$ in rev for 2021. 1.5B is not nothing but not > 5% of revenue for the year. ie bulk of it came from actually making and selling cars.

tax credit: the US federal govt had a tax credit program which was lobbied by GM in the 2010's that gave car buyers 7.5K as a tax write off . this was only eligible for less than 100k cars sold (tesla sold 405,300 in q4 2022) and was only useful if you made enough income where a tax writeoff made sense. 2023 new laws are in place with more rules which makes them almost useless (or only useful for those who lobbied for it).