you got the advantages of autotrade this day...
make 3 or more vending slave it wont take days to make 1 char of merchant to get vending skill,
vend GJ and meat, GJ at 169 to 175 depend on the competition or how long you expect them to get sold, ill recommend 169, set all the venders at various place, check them out every 4-5 hours or whatever you wanted too, i belive you will get 200-300 thousand zeny gain per vendors with 500k capital per vendor. That 600-900k gain if you set 3 vender. meanwhile you can hunt other thing with other char, and I thing razer zeny guide for newbie still relevant.
i believe you could gather 1-2 mil a day even if you are gearless, in a week you will get 7-14 mil, if you planning to make like 5-6 vendor your income will be doubled, that is 14-28 mil per week.
btw iirc you need like 154 to make 1 GJ