You are asking a couple of different things...
a) What you can afford per the BANK is different than what you can afford per your personal financial goals... So that would be a conversation to have with a lender. Not only what you are qualified for, but what you want to pay from a personal finance standpoint.
From the BANK point of view, the amount you can buy is dependent on what is called your "debt to income ratio". That is, the max percentage that your house payment in addition to monthly car payments, credit cards, etc, makes up of your total gross income.
So, it depends on a number of things. A) what is the max debt to income ratio for the program you are looking for? Conventional is between 45 and 50% maximum DTT; FHA is about 55%, and VA is more like 60 to 65% maximum.
B) Do you have enough down payment to avoid mortgage insurance? Does your home have HOA's? That will affect your purchase "bandwidth" for lack of a better term.
C) What is your Debt? Do you have any debt at all?
These are all really important questions that will help you determine what you can purchase. The good news is that you dont have to figure it out on your own... But, I can help you understand the math.
Lets use conventional lending, no HOA, 20% down.
50K per year is 4166 per month.
Lets use 300 dollars in "debt payments" (credit card minimums, car, etc.)
Conventional max DTI is 45%.
4166 x .45 = 1875 (this is what you have available for house payment AND debt)
-300 (to strip the "debt" out of the equation)
1575 is what you have "available" for your total mortgage payment INCLUDING taxes and insurance.
TYPICALLY, taxes and insurance make up ABOUT 20% of a payment. SO, if I take 1575 x 80% I get your payment for Principal and Interest ONLY.
1575 x 80% = 1260/mo mortgage payment (excluding taxes and insurance)
Conservatively, that is a loan amount of approximately 270,000 dollars. (Not including HOA, mortgage insurance, etc. if applicable).
Hope this helps so that you understand HOW it works, but you really just need to speak with a good lender... They can do all of this for you (I would hope).
Have a great day!
WJ Bradley Mortgage Capital