I just purchased a Sony Sony RDR-GX360 and discovered it was tunerless.

My TV has the Red Yellow Green Composite ports on the back, but according to the DVD Recorder manual, I will either need a Cable or Satellite box to plug the DVD REcorder into in order to record live tv.

I currently receive Comcast cable (without a cable box) that plugs right into the T.V. from the wall.

I was wondering what the lowest cost options are available. For instance, I have heard that I could get a Digital to Analog converter with a governemt coupon, but I am not sure if this would solve my recording problem since I get my TV through comcast and not Antennae. Also, I am not sure if this converter is the same thing as a "tuner".

I am new to the AV scene, but I am eager to learn.

Can anyone point me in the right direction? Any input would be appreciated.

Yes, the digital to analog converters that you can get government coupons for are tuners, but only for digital over-the-air broadcasts that you get with an antenna. They can't pick up cable TV, either analog or digital.

If you're still within the time window for returning your DVD recorder for exchange or refund, I strongly recommend that you return it and buy one that does have a tuner. As far as I know, all current models with tuners can receive both over-the-air and cable TV, whether analog or digital. So you should be able to record the same channels that your TV can receive with its tuner.

Since you are using Comcast cable you may want to inquire about renting a cable converter box through them. A Comcast converter box will have various outputs that will allow your tunerless DVD recorder to record from a "line input." Your TV needs to have the same "composite" inputs, yellow for video and white and red for audio; or the red, blue, green "component" inputs paired with the white and red for audio.

If your TV has only the (threaded) RF coaxial cable input you will need a modulator (around $25) in order to work with your DVD recorder.

The alternative, as stated by jtbell, is to exchange the DVD recorder for one with a tuner.

if you're looking for a "lowest-cost option" DVD recorder with a tuner, and the option turns out to be one of the Funai-made models, don't be surprised to find that it either doesn't pick up or stably keep in it's memory all the clear-QAM channels. It'd probably be safer to spend a bit more and get something like a Panasonic, or something else you never really hear about people having that problem with.

I second the recommendation to up your budget if you want a QAM tuner- the dirt-cheap recorders with QAM are a waste. Go with something like the Panasonic EZ28 ($200-ish) or the Phillips 3576/Magnavox H2160 ($250-300). The latter two include a hard drive which is very useful. They are made by Funai, true, but are flagship models with more consistent quality control. The Panasonic has an arguably better tuner, but (current) Panasonics are known to be bug-ridden with other issues. At this point in time, none of the recorders has a totally great ATSC/QAM tuner, they're all still new-ish products with teething pains: its not the best time for those who subscribe to the budget "boxless" cable tiers, especially since cable vendors are all but ignoring the QAM concept anyway. Short term, I'd recommend keeping the tunerless recorder and spending the extra few $ per month to rent the cable decoder box until the dust settles next year: its more reliable than the QAM gamble in many areas, especially if you don't have the scratch for one of the three better-grade recorders recommended for boxless QAM. Most cable decoders have multi-event timers, and while its a pain to set timers on both the recorder and the cable box I'd rather do that than risk the cable company screwing around with the "boxless" QAM feed when a really important program is scheduled.

I totally agree with Citibear. I also think you'll be getting less and less analog cable channels in the very near future which is mostly what a tunered DVDR would be able to receive.
The one pain with cable STBs would be that many do not output Wide Screen over anything other than component or HDMI outputs. This means you'd be getting a postage stamp effect on wide screen broadcasts via the STBs S-video or composite outputs.
I believe Wajo had a thread going a while back trying to document the various cable STBs and which ones did and didn't output WS over S-vid/composite outputs. You could try and ask your cable provider but I doubt they will know what you're talking about.
http://www.avsforum.com/avs-vb/showthread.php?t=1067919&highlight=

If Analog Cable TV is your choice of source, go to the GoodWill and buy a Stereo VCR for about five bucks. Doesn't matter if the tape part is good, as all you need is a tuner...