The answer will very much depend on where the original poster lives.
If they are in the US, Canada, Mexico or Korea - then OTA TV is broadcast using 8VSB ATSC standards. There are some USB tuners available for this (though choice is more restricted and prices higher than those for other standards). Alternatively there are network tuners like the Silicon Dust HD Homerun, but they aren't cheap. US OTA broadcasts are in 480i, 720p or 1080i MPEG2. With an MPEG2 licence the Pi has no problems with this format - though for high quality 1080i deinterlacing a Pi 2 with overclock or a Pi 3 will deliver better results than a Zero or a Pi A/A+/B/B+ (as they drop to a lower quality deinterlace on 1080i)
If the OP is in Europe/Aus/NZ - then most of Europe uses DVB-T, with some areas also using DVB-T2. Most countries are using MPEG2 or H264 compression which the Pi can handle. Germany is the exception as they are transitioning from DVB-T MPEG2 (which any Pi with the right licence can cope with) to DVB-T2 with H265/HEVC compression (which the Pi can't handle in hardware, and software decode pushes it too hard) Germany is also using 1080/50p for some HEVC/H265 channels (which the Pi definitely can't handle with HEVC software decode) In Europe 576/50i, 720/50p and 1080/50i are being used for H264, with 576i being also used with MPEG2. Same advice for deinterlacing 1080i as above (though 720/50p needs no deinterlacing and is great on a Pi first gen or a Pi Zero - so in places like Sweden and Norway which are 720p and 576i there is no deinterlacing issue on Pis with the single-core SoC)
It the OP is in South America - then most of that continent is using ISDB-T (a modified Japanese standard) that uses H264 compression. There is some support for ISDB-T USB tuners, but because fewer people use them, it may not be as easy to set-up.
If the OP is in Japan - don't bother. Although Japan uses an older version of ISDB-T, all Japanese OTA broadcasts are, I believe, encrypted and require a viewing card. I don't think this is in scope for current Pi-based solutions.
A good guide for DVB/ATSC/ISDB tuner support is the Linux TV wiki : https://www.linuxtv.org/wiki/index.php/ ... nformation
(NB ATSC and ISDB-T tuners are included in the DVB section - as DVB digital tuners arrived first I think)
For VGA output then there is a choice of a cheap HDMI to VGA converter, or a Gertboard. I suspect the HDMI to VGA approach may be easier.
In software terms, LibreElec with a built in TV Headend front-end will probably do a pretty good job, as I think it includes both ATSC and DVB-T/T2 drivers and compatibility - though I would check specific support for the USB tuner you consider buying before buying it.