To begin, you'll need to figure out what your gross income is (before taxes) monthly and yearly.  To get a quick ballpark figure, take the yearly income of yourself - and your co-purchaser if applicable - and multiply by 2 to 2 1/2.  Most people will fall into this category.  There are other things to consider, however.  If you have a large down payment combined with little to no bills, the lender may believe that you could afford a more expensive home than the ballpark figure allows.