Today I went to a language exchange and a nice lady from Beijing told me to use 掙錢 instead of 賺錢。 I asked whether the latter was 口語 and she replied 賺錢 was something one said “just like that”. So now I am confused.
For 掙錢 pleco defines: earn (or make) money For 賺錢 make money (or a profit)
The first one does sound a bit more like involving work, but I cannot really be sure of the distinction.