NEW YORK >> Free services let you watch thousands of movies and TV shows online, but using them feels like wandering through a low-rent, digital version of Blockbuster (RIP).

Reality TV, long-forgotten “classics” and movies that never made it to theaters — these are the types of lackluster shows and movies you’ll find for free. But finding gems in the junk, like the original “Roseanne,” can give you a treasure-hunting rush.

Unfortunately, websites and apps for many of the services have poor designs and search capabilities — not conducive to finding those gems. An outside search aid such as Roku, Reelgood, Decider and JustWatch can help scan multiple services to see which ones have the titles you want.

Once you find something to watch, you’ll have to put up with commercials. You’ll get fewer ads compared with traditional TV channels. But online ad breaks sometimes interrupt people speaking, which is super annoying. And these services may also track you to target ads.

But as entertainment costs rise — especially as AT&T, Disney and Apple introduce new video subscriptions — free is hard to turn down.

Here’s a look at some of the best-known:

CRACKLE

What’s on: “Classic” movies and TV shows, along with some originals — although the best-known, Jerry Seinfeld’s “Comedians in Cars Getting Coffee,” is now on Netflix instead. You can browse movies by broad categories like “action” and “drama.”

How odd: An “up next” feature plays something else after you’re done watching. But instead of bringing up the next “Who’s the Boss” episode after finishing the pilot, it landed on the movie “Ali.” And despite what the search results tell you, Julia Roberts is not in “El Mariachi.”

PLUTO

On demand: The original nine-season run of “Roseanne” (but not the recent reboot) and some appealing movies from the past few decades like “Election,” ”Short Term 12” and “Heathers.”

Live TV: Pluto is unusual in that it also offers dozens of channels with “live” video. Though some of these are pretty niche, dedicated to Minecraft or cats, the service is owned by Viacom, so you also get shows from well-known Viacom networks like MTV and Comedy Central. There’s an entire channel dedicated to MTV’s “The Hills.”

Finding video: Good luck. There’s no search tool, though Pluto says it’s coming.

How odd: The TV guide only shows what’s on in the next 90 minutes, and you can’t pause, rewind or fast-forward the video.

TUBI

What’s on: Fun retro stuff (I do love “Problem Child”), prestige films from past decades and some old hits. A tenth of the library changes every month.

Finding video: Movies and TV shows are organized into useful categories, some with cheeky themes like “Cult Classics” or “Not on Netflix.”

Ad interruptions: It’s great that I can fast-forward through scenes without being forced to watch an ad. Other free services often show ads when you jump ahead. TV episodes that I watched only had ads before the show, not during it, but that doesn’t mean the same will happen for you.

How odd: A third of the movies brought up by searching actor John Ritter came out after he died. His ghost is not in them.

VUDU

What’s on: The Walmart-owned service sells shows and movies, just like Apple’s iTunes and Google Play, but there’s also plenty of free TV shows and movies, with such categories like “Westerns,” ”Anime” and “Kids TV.” Vudu will also introduce original content this summer.

Those ads: Though ads will break up movies, they didn’t interrupt the TV shows I watched. Rather, as with Tubi, the ads were all shown before the episodes.

How odd: Different seasons of TV shows each get their own tile, making me scroll more to find different shows.

BEYOND THAT

There are many, many other free services, including ones that focus just on children’s video (PBS Kids) or local news (NewsON). Here are a few that will have broader appeal:

>> YOUTUBE is the world’s largest free video site, but it’s not the best place to find full versions of traditional movies and TV series for adults. Its selection of free movies is small and uninteresting (Find them by searching for “movies” and looking for the “free with ads” tag). YouTube also streams live events and plans to make its original shows free.

>> HOOPLA and KANOPY technically charge for viewing videos, but it’s your public library that pays for it. It’s free for you with a library card. The movie selection is noticeably better, particularly Kanopy, with recent critical favorites, though don’t expect the latest Marvel or “Star Wars” blockbusters. No ads, but libraries limit how many you can watch each month.

>> YAHOO VIEW is Hulu’s old free business, with a few recent episodes of broadcast-network shows. You can watch only on a traditional computer, not a mobile or streaming device.

>> The ROKU CHANNEL with live channels and on-demand movies and shows. It works on computers and mobile, so you don’t need to own a Roku streaming device.

>> Amazon-owned IMDB FREEDIVE has on-demand movies and shows, but not as extensive as what you get with an Amazon Prime membership.

>> LOCAST streams over-the-air stations for ABC, CBS, Fox, NBC, PBS and others in Baltimore, Boston, Chicago, Dallas, Denver, Houston, New York, Philadelphia and Washington. Ads asking for donations interrupt what’s on TV.

>> Facebook has a WATCH tab with cult favorite “Buffy the Vampire Slayer” and Jada Pinkett Smith’s talk show, but it isn’t easy to use or tell what’s available.