How much can you make working at home? I don't know. I can tell you what it is like for me and that is about it. It took me almost 6 mos before I ever saw a check when I started my website. Thank goodness for the daycare business! If you start something like a daycare business you can expect to see money right away obviously. With the website I remember when I made my first $45, I was so excited I called everyone!
It is really up to you to decide how much you will make. If you are in direct sales and do 20 parties a month and push the sales you would probably be able to see a profit the first month even after putting some of it back into your business. If you work in affiliate advertising and spend a good portion of your day (6-8 hrs) promoting it, you might see a profit the first month too. I think realistically, in affiliate advertising though, you are going to spend a lot of time just trying to find a good place to advertise. Once you do though, watch out! It will come in faster than you can imagine. Last month I hit upon a great place to advertise for one of my affiliates and made over $400 over a two day time frame. I was amazed with that one! Keep in mind, the affiliate was running a fantastic special so it worked. This month they have a pretty blah special and I am not seeing nearly that kind of return.
If you build your own website to advertise for affiliates and plan to just promote your website, expect to put in 8-12 hours a day and still not see a profit for close to a year. It just takes that long to find good places, build a good reputation, get into all the search engines etc.
No matter what you do, if you put in time, energy and research you will be able to make a decent amount of money.