If i buy 4 new tires do i need to do a wheel alignment ?

If the previous tires wore evenly, then no, there is absolutely no reason to waste money on an alignment. An alignment is done when the steering is not setup properly, and you'd know through the steering and tire wear if that was the case.

Tire rotation is not needed when you get new tires, but you may need an alignment. Here's how it works at any good tire shop. Ask the tire shop guy if the way tread has worn on your old front tires shows there is an alignment problem. Takes about one minute and it is free. If he says yes, have him show you the tread wear pattern. The ask him to show you the picture book he has that shows tires worn by bad alignment and ask him to show you the picture of the bad tire with wear just like yours. If he can do that, you need an alignment as soon as the news tires are put on. If he can't show you the tell-tale wear pattern, then you don't need an alignment.

btw Major brands are all the same, so go find a four tires for the price of three sale or at least a sale with a $100 rebate. The reason major brands are all the same is because they all give you the same relative mileage warranty for each class of tire they sell. And with that warranty you pay for the miles you get to drive and get a credit on new tires for the miles you don't get to drive.

If the tires were look good and was not wore out on the inside or the out side you should be find and the steering wheel was in the center its ok and its not pulling to one side or the other ,after you put new tires on you will need to do the rotation about every 5,000 miles to make the tires last longer ,

No one here can tell you if you need an alignment without inspecting the tread wear on your old tires. Rotating tires is done to keep tread wear even on front and rear tires. Usually every 6 to 10,000 miles.

4 New Tires

It is always a sensible idea to get an alignment when purchasing news tires, especially if one has not been performed in 40k miles. Protect your investment.

Need? No.

Should? Yes.

No you don't