PlutoTV app has no relationship with your DirectTV subscription. It simply needs broadband. It is completely free TV paid for by the commercials that run on it. You can access it on your Mac now through a web browser to get a very good feel for what it offers before choosing a set-top box.
Another good app to pair with it is Stirr, which shares some of the same channels but also has many others. It too is completely free TV paid for by commercials. And it too can be fully sampled through a web browser so you can get a good feel for what you can watch on it.
And there are several other apps that work the same way: some already mentioned by others and apps like Crackle or even Redbox (app) has a selection of free channels to stream too. Generally, if they are free, their revenue is commercials. And some of them will slug commercials in right in the middle of scenes vs. waiting for the natural commercial breaks. This can be abrupt but then will pickup where it should when the shows come back again.
None of these will have many satt/cable channels you may like, and few if any of the major networks (CBS, NBC, ABC, FOX, CW, PBS). You might get ONE of those... maybe 2 of the majors depending on location. Stirrr will generally offer at least some of ONE local channel. In my area that is my local CBS station.
You might check your local network websites to see if they have their own app. If they do, check to see if you can watch their live broadcast through their app. That might be a way to get that network for free (paid for by the commercials that run on it).
You might also use a website like
antennaweb.org, punch in your address and zip code and see what you can pick up with an "old fashioned" antenna. Often this will be the best quality HD you can get for free- even better than getting the same channels via paid satt/cable. Depending on location, you might discover you can get all of the major networks and a bunch of sub channels that sometimes have great classic programming on them too. All of that is free (paid for by commercials that run on those channels).
If you go that way, you might want to buy yourself a tuner(s) from SiliconDust called
HDHomeRun and then use their app or great options like the
Channels app or Plex to manage your local channels. I personally love Channels, into which you can fold Pluto, Stirrr and others and have a
single programming guide showing you everything that is on for all of those free services.
If you dig into that just a little deeper, you'll discover that you can allocate a variety of hard drive storage options to act as a DVR. This can make it easy to
store stuff you would like to watch later- just like using a DVR with paid cable or DirecTV, minus their expensive lease fees and needing a lease box on every TV in the house.
There's also Channels & Plex apps for mobile devices, so you can stream your channels to your mobile devices, even when away from home (including being FAR away from home).
All that can deliver hundreds of channels for free (commercials pay for the programming). What will be missing is more popular satt/cable networks and the major networks if you can't get them via over-the-air (antenna) or via their apps if they have one (and if it live streams their broadcast which is not always the case).
If there is something you really love not available that way, you might be able to buy a subscription to a service that offers that one channel or that one show or a group of shows. For example, some people really love some of the programming on the Discovery networks. So for a relatively cheap subscription to their app, you can get those kinds of shows without a cable or satt subscription. Some people really love one sport, so apps like NBA league pass or similar can buy you access to your favorite team's games for the season.
These days there is quite a LOT to watch without having to pay a nickel for the services. If you can be happy with those options- often a lot of classic television instead of brand new productions and live sports- cutting the cord and still having plenty to watch is realistically achievable. A lot of the most popular shows and select live sports are available free on the local networks which can be tapped with an antenna for people who live close enough to a city to get them. I get about 50 free channels via antenna that I actually like: all of the major networks plus a pretty good mix of classic TV/movies on sub channels like MEtv, Comet, Charge, Cozi, Mystery, Story, Decades, H&I, Buzzr, Laff, GetTV, Weathernation, Grit and others.
As to AppleTV vs. ROKU, asking here is going to get you Apple bias. I have both and strongly favor AppleTV myself, mostly for many other benefits beyond only watching streaming television. However, since dollars seem to be influential in the decision-making, ROKU is much better at gathering together free streaming television "channels"/programming to watch than AppleTV, which generally wants to sell you movies & TV and/or rent them. ROKU simply has a lot more of free programming focus than Apple. So if that's the bulk of the interest, you'll probably get more out of a ROKU device.
AppleTV simply "just works" better with Apple ecosystem. It nicely connects with your own stuff on other Apple hardware so you can easily enjoy that as well. But tvOS is definitely much more biased to generating revenue than trying to maximize free TV viewing.
I hope this is helpful.
