A lot more factors come into play than just a house payment. Do you have a down payment of at least $3,500 available? Do you have another $2,000 or more to cover unanticipated expenses? Then you have closing costs. Although some people are getting the sellers to pay for those, what if you have to pay them, do you have well over $1,000 to cover those also?
I wrote three blogs I think could help you. Take a look.
This one covers the steps needed to buy a house. Simple, east to understand steps anyone can follow. I also give a very simple way to figure out just what you can afford for a safe monthly mortgage payment.
This blog gives things to do and consider when you are going to buy a house some time in the future.
This gives some iedas about how to build up a down payment.
First thing you need to do is consult with a lender.
Even though his income is $20K/year, his employment history, debt ratio, FICO's, etc. may impact the "bottom line" net worth he actually makes.
Once you get discuss this with your lender, they will be able to tell you how much you actually qualify for.
It'll save you alot of time in researching a home plus when putting in offer's, you are required to submit a pre-approval letter showing how much you qualify for.
Best of luck!