You shouldn’t think of the number in dollars, you should think of the number in percentages. The question is, what percent of your monthly income can you invest? We typically recommend that you invest between 15% and 30% of your monthly income. Get into the habit of treating your investment portfolio as an essential budgeted line item like your mortgage/rent, cell phone bill, and heating bill. Continuous contribution to your investments is important if you want to retire. If you don’t have a lot of money to start with, that’s okay. In that case, start with $1,000 and go from there.