Att direct tv equipment

This is the directv community forums so you should post on the AT&T Community Forums under the TV category for U-verse on how the cancellation procedure works. 

As far as bundling AT&T wireless with DIRECTV STREAM, you can but I believe that the discount is only something like $10 or $15/month (obviously better than nothing). 
more info for bundles available here:

https://www.directv.com/internet-bundles/?source=EDDSDIDEB00TFAGJP&wtExtndSource=directv+stream+internet+bundle&gclsrc=aw.ds&gbraid=0AAAAAoX5dNR0G3addeVFeCYE8VAwNKJVA&gbraid=0AAAAAoX5dNR0G3addeVFeCYE8VAwNKJVA&gclid=CjwKCAjwiOCgBhAgEiwAjv5whG186R1nCA96pxrUjQ5YDRYmJYBxkzWjlhpqebDKwJcqMC64CYj_bRoCG5sQAvD_BwE&gclsrc=aw.ds 

I am well aware of how to cancel.  What I wanted to know is what equipment is required as well as cost.  Have I misunderstood what this forum is.  
I have three smart TV’s and need to know is a box of some sort needed to make them work.  I  don’t want to sign up for direct tv streaming without knowing what to expect. 

All the questions you are asking are easily available on the website. Cost depends on what equipment you want and which subscription that you desire. 

I am just trying to make good decisions maintaining a tv service. U-verse has increased their charges and rumor has it AT&T will  discontinue U-verse sometime soon.  My calls to AT&T usually are with someone I can’t understand and after their sales pitch on something I’m not sure I want I leave the call. If that offends someone here I’m sorry.  
On my AT&T service I have the router/modem gateway and a U-Verse receiver connected by cat5 cable.  From the receiver it is connected to a Sony AV box via HDMI cable then to the TV by ARC HDMI cable.  The reason for my MISUNDERSTOOD question was to be sure if I decide to go with Direct TV Streaming I could make all this work.  Also I am considering using Cox internet to stream other TV service.  By the way much cheaper and a lot faster (I’m limited to 24mbps with AT&T). Cox said they furnish a contour box to do the live streaming and my car5 and HDMI cables will work. 
If I am off base with any of this I would appreciate knowing. 

I am in exactly your same situation.  U-verse has gotten so expensive, and with the $40 promo I was able to talk them into last year expiring on April 10, and the only discount they offered now being $20, my U300 would go up to about $180- ridiculous. I am on the DTV 5 day free trial now, and there is a promo for new customers wherein you get the box for free (1). I like the quality so far, but have had some login issues. I suggest you try it (you can get up to 14 days' trial if you call in instead). That was the only way I could think of to find out how well it works in the wild. There are many U-verse like similarities. ATT actually transferred me on a call to DIRECTV, because apparently even their customer service people think U-verse isn't worth it any more (and as you say, it will sunset sometime, maybe sooner rather than later.) BTW- you might also look into Google fiber for quick (1000 up and down for $70) internet to go along with it. Their VOIP phone service is also only $10 vs. $57 with fees on ATT. Good luck with your quest!