Depends on your income.
I just took over a new team (moved to new country). So I am investing 10k per week because I think I know how to handle my finances.
5k per week will do you until you start bringing in more money.
For everyone, I think a good way of judging how much you should spend is by looking at your merchandise revenue. If you are winning you need to invest more because you will get lower picks AND your merchandise will be going up because you are winning.