There are so many answers for this question... truth is, one size doesn't fit all!! As some of the other replies indicate, working with a qualified Realtor will be a great option. If you are not ready to engage with a Realtor just yet, then there are calculators online that can help you guestimate the kind of program you may qualify for and the associated down payment requirements. Or, do you have an existing banking relationship? Contact the mortgage department...
Congratulations on your decision to make a home purchase and realizing preparing your budget is a HUGE first step; that will start you in the right direction!!
Best of luck,