Making a "home theater" need some help

[KEW]

I am definitely for buying one piece at a time but isn't it hard to do that with a receiver? You kind of have to have one haha what order should i go in? I mean I could by my mains then use the receiver from my yamaha HTIB then should I buy a new receiver then a center etc or center then receiver.... i think you know what i mean

Get a good deal on a receiver. The Marantz Grant recommended looks like a good option.
This receiver will likely be all you need, but that does depend on your speakers, how large your room is, and how hard you are going to push things (how loud).
It is rare for a speaker in your price range to be problematic for a standard receiver. There probably are some exceptions, but companies know consumers buying speakers at around $1000/pr or less are going to be driving them with mainstream receivers.
Furthermore, if you are putting a sub into the mix, you are offloading the bass from your main speakers. This saves substantial power requirements from the receiver (it takes much more power for the lower frequencies).
So, get a good receiver like this. It will probably do all you need. However, be prepared, if you buy speakers which drop to low impedance, and, especially, if you don't use a sub, to add an external amplifier to be able to crank it.
Definitely make sure the receiver has pre-amp outputs so you can connect an external amplifier (the Marantz SR5004 does).
Frankly, if I needed more power, I would always go with an external amp before spending more money on a receiver - the pre-processors in receivers are complicated and thus the potential for problems is greater than an amp and a good amplifier will last decades while you will be lucky if a receiver is not obsolete by the end of one decade (but that mainly depends on your needs/wants).