Combining the chief interests of economy, convenience, and reasonable quality, your best bet would be to just grab any CRT television set locally,
that has RCA inputs for video and audio. The cable that shipped with the computer originally is RF (antenna, channel 3) and is less-than-ideal, to be sure. Between Craigslist and the Goodwill store, just a few dollars will give a nice composite connection much superior to tuning in to channel 3. In this era, people are practically giving away so many CRTs that you can be cheap and choosy at the same time, and find one with "good" inputs.
You will need a composite video cable. There are some different types, but the simplest/cheapest is like this one advertised on Ebay right now for $6 + $6 shipping:
eBay Auction -- Item Number: 170278575590
This is advertised as a "Commodore" video cable, but for the simplest composite connection they are the same. The fact that this cable advertises for VIC-20 is reassuring that it will work on an Atari computer.
Quite simply, I did not see anybody on Ebay advertising ANY Atari computer video cables at all, except for the store that I will mention in a moment, that has some problem and isn't delivering or answering emails and you don't want to order from them.
As you get "fancier" in the connection, things become more complicated. If you get a CRT television or other monitor that has S-video connection, you would need a different cable to take advantage of it.
Commodore cables are different and incompatible with the Atari at this point. These cables are also a bit more expensive and harder to get. There is a store on Ebay that lists them, but they are having some kind of great difficulties now and not shipping orders, answering emails, etc. I have an outstanding order with them for 3 cables (2 of which are these S-video cables) and I am currently wondering if I am going to have to file a claim to get my money back. Just so you'll know, the store is:
[click to open link]
eBay Seller: atari-commodore-n-morestore
Go ahead and look at their inventory to see what is available - they have (had?) great cables in the past and it's too bad they're not available somewhere else.
If you get a Commodore 1702 - which is a fantastic monitor - you'd need a cable similar to the S-video cable to get the best display out of it - although the "simple" composite cable I first talked about will work without taking advantage of all the quality the montior has to offer. The 1702 predates the S-video standard connector, although it functions with S-video signals and quality. The cable to do this simply routes "S-video" signals over 2 RCA jacks for video, instead of one. This is typically referred to as a "split chroma/luma" cable. Picture quality is fantastic, just like S-video on a monitor that takes that little round connector. But go ahead and price one with shipping and get ready to take out your wallet, and good luck finding an Atari cable to get the best quality.
Just so you can see a listings for such a cable and see what they look like, here is a listing from that above store - for Commodore 64.
eBay Auction -- Item Number: 250534578906
Once again, this cable WILL NOT WORK ON AN ATARI and I was only pointing to the auction for reference so you can see what the cable looks like and is called;
you want a similar cable to this but for Atari if you were going to use a Commodore 1702 monitor. The Commodore (either S-video or chroma/luma) has a different number of pins on the round DIN plug that plugs into the computer for these cables. I had messaged this store on Ebay (prior to whatever problem he is having now) and asked him if he COULD make one for Atari and he said "yes he could" and then send me an Ebay invoice. Too bad, as now he can't even ship what is listed on his site.
Someone else may have some better suggestions, but I would suggest that you go with the $6+$6 VIC-20 cable and then you can hook to anything with RCA jacks. You can then "upgrade" your cable, monitor, and connection in the future. Frankly, I don't know of *any* other Atari monitor cables for sale right now, since that store crapped out.....and they were **EXCELLENT** in the past. Hope this helps a little.
Edit: Forgot to suggest: If you end up with a stereo TV or monitor it will have 2 audio-in jacks and the computer is mono so unless you don't mind sound coming out of one speaker, I'd suggest a small Y-cable RCA 1-female-to-2-male like this. It always bugs me to have sound coming from half the TV. Of course old monitors like the 1702 are mono so don't need this:
eBay Auction -- Item Number: 290404711843
Edited by wood_jl, Sat Mar 20, 2010 10:25 PM.