Mortgage/Monthly Payment question Please help?

Tiffany ;figures ;she ;can ;pay ;$1,000 ;a ;month ;for ;housing. ;She ;used ;a ;mortgage ;calculator ;to ;figure ;out ;how ;big ;a ;mortgage ;she ;could ;afford. ;Tiffany ;sees ;that ;at ;current ;interest ;rates ;a ;$150,000 ;mortgage ;would ;be ;a ;payment ;of ;$800, ;and ;her ;estimated ;tax ;payment ;each ;month ;would ;be ;$100. ;Tiffany ;thinks ;she ;can ;easily ;afford ;the ;$900 ;total ;monthly ;payment. ;Describe ;three ;costs ;she ;did ;not ;consider ;in ;her ;calculation.