I just opened a thread on ATMB about it. Definitely something hinky going on - if I hover over your link, it says walmart.com. But if I try to quote your post, the text in the quote box is clearly going to amazon.com.
Go to your local Goodwill and they’ll have a bunch of old RF converters that will do what you need for just a few dollars. Someone there can probably help you find one that works for you. You want to convert your composite signal (yellow, red, white) into channel 3.
They will also have input switchers which look a bit similar. A switcher is something that can take composite inputs from multiple devices (vcr, dvd, etc) and output to a single composite output. There will be a switch or button which lets you pick which input is sent to the output. Sometimes the switcher can also output to coax, so you may be able to find one of those which works as well.
If you get one at goodwill, make sure it comes with the needed power supply. A switcher doesn’t always need power, but a coax converter always does since it takes power to run the electronics to do the coax conversion.
And if you’re at goodwill anyway, you could probably pick up an external VCR for almost nothing. With an external VCR, you could get a new TV that takes HDMI directly.
Many VCR’s will actually work as a composite->coax converter. They often have both formats as input and output. So an external VCR could act as a coax converter to your old TV now and as a VCR once you get a new TV which could take HDMI directly.
Also at Goodwill (or craigslist), you can find unlimited old TVs. Likely you can find an old TV for pretty cheap that has lots of inputs and a built-in VCR.
I get ten channels with an antenna, six of which I never watch …
If the converter does not work out, most, if not all, new flat screen TVs have composite inputs (yellow RCA Jack) that should work with VCRs (unless really ancient).