Is it Bad to LowBall on Houses?

[Dylan NA]

So lets be honest, majority of houses that are sold on real estate websites, are either overpriced or just simply not worth their value. am curious is it bad to constantly low ball on prices for houses? For example, I asked a seller, if he would take 225,000 on his 250,000 property. Now if he does sell that is awesome, I just got a very very good deal, if he doesn't whatever. Is this the strategy I should typically use when buying houses? I would never ever offer someone the actual price they want on a house, I would always low ball around 20-25,000. In order to do well in real estate we need to get very very good deals on the houses we buy. If I tell the person I will buy there house instantly for 225,000 and its worth 250,000 maybe 7/10 people wouldn't do the deal, but theres lots of people who aren't patient and would accept the deal.
What is your opinion on low balling every house offer, until you find a deal you like. Do most of you lowball? im curious to know.

As for the property I am looking at its going for 250,000. It has 2 bedrooms upstairs and a suite downstairs with 2 bedrooms, I asked if the suite in the basement is legal too btw. So I could charge 1,300 dollars for the upstairs and 1,300 for the the basement. That leaves me with 2,600 gross income a month. Lets assume 400 dollars in total bills, 200 dollars for property tax, and 100 for house insurance.

That's 700 dollars in expenses, now lets assume I paid 250,000 instead of 225,000. My mortgage would cost me:

250,000 x 20% downpayment= 200,000 mortgage a month= 980 dollars

now lets assume I got it with 225,000 x 20%= 180,000 mortage= 880 dollars a month

Total expenses now would be: 880 dollars a month, + 400 dollars, 200 dollars, and 100 dollars= 1580 dollars. plus 225 dollars for property manager= 1,805 dollars for my total expenses.

So I would make 800 dollars a month net. 

What do you guys think of my idea to constantly low ball on prices?