I've only tested this for Sigurd but it should work for the whole gen 1 cast. This presumes you have a place to enter action replay codes.
Money has 2 codes for each character
Sigurd:
7e2d4bXX & 7e2d4bcXX
The first code has to have 50 and the second code has to have C3
So it would look like
7e2d4b50 & 7e2d4cC3
This would fix Sigurd's money at 50,000, which is the money cap for any character (nothing should cost more than this)
Giving everyone bargain is actually harder, because I still haven't found the skill modifier codes for gen 1. If you want them for Gen 2, those are out there, but Gen 1 is outta luck. I also have a few codes for when Annand shows up in chapter 4 if anyone is interested.
Anyway. List of money codes for everyone else in Gen 1. Credit to that one gamefaqs list of cheats by Lord Alvein, the only thing here that's mine is the entered values and the localized names.
Rare
