try this link here for more settle differences Radio Shack Scanners - The RadioReference Wiki
and the pro-97 is on deep discount due to it is discontinued i got mine for $30 about a month ago, good luck though, you might have luck, go to your local radio shack and have them do an inventory check on area stores, that option is NOT available on their website, have them look up the SKU # 20-527, if they look up pro-97 the search will not work, the pro-97 is a great scanner for $30, good luck and happy hunting!
There are a lot of threads here on RR related to this exact question.
The PRO-164, which is the same as the GRE branded PSR-300, is an updated PRO-97. The radio portion is nearly identical, the LCD display was upgraded, and the CPU was changed. The new CPU allows for field upgraded firmware. The new display incorporates an "S meter". The '164/'300 can receive in the 700 MHz band.
If you want to monitor an 800 MHz MOtorola type TRS, you might end up requiring the '164/'300. If you are monitoring EDACS or LTR only, then the '97 will work just fine.
The PRO-97 can be programmed using the COM version cable or the USB version cable; the '164/'300 requires the USB version cable. You can probably find a PRO-97 out there for about half of the typical cost of a PRO-164.
$30 for a 97, I'd buy em all, just for all the other features of a conventional scanner. The 164 is a great trunking scanner! I hear the arguments about programming by hand, don't even try.
Get win97 and study it and you will get a real feeling for how the radio is programmed and how it works best. Programming by hand is an easy way to program insufficiently.
i would have bought more than one but there was only one in my reasonable area, i have a pro-95 and the pro-97 my next one will probably a pro-164, but i still program them the manual way yet, i have win95 and win97 on my wife's computer but i cant get her away from her computer long enough for me to do what i need.