I would suggest going the keypad route as already mentioned. It will help you save money, especially since you plan on saving for a digital scanner. Be sure to check the blue links for step-by-step instructions.
You first need to go to create a
a new TSYS. It will take you to a brand new menu, where you have to follow
these instructions as closely as possible to ensure that it works properly. After you finish and hit
Save, you then go through the TGRP menu and program it following
these instructions. Just create addtional TGRP as needed and you should be on your way.
If the above doesn't help you, try out
this. While the instructions are fine tuned for the PSR-500/600 and Pro-106/197, the basic concepts of the object oriented programming remains similar. Take your time and follow along the best you can. It can be very irritating at first, but once you finally get how programming works, you will be able to program new talkgroups easily.
For the cables you are seeking, you need either:
RadioShack USB-PC Scanner Programming Cable : Programming Cables | RadioShack.com
https://www.greamerica.com/shop/cgi-bin/cp-app.cgi?pg=prod&ref=scan006
I've also seen a couple of posts here and there saying you can get older model cables for around $7 in a few RadioShacks, but it is in no way guaranteed.
Be advised that you
will need to
BUY additional software to program your scanner such as:
ARC310
PSREdit310
Win500
With buying the software, you will still need to manually enter what you want to program unless you want to consider becoming a premium subscriber to RadioReference at a cost of $15.00 for 180 days (or $7.50 by mail for 90 days) to do a direct download from the database. This could easily cost a total of over $50.