From my experience, 2 GP (which is the same as 20 SP) is the normal starting money. But, some of the races have that in different forms, like the "Common Man" who has it in the form of livestock (pg. 86, RMFRP corebook).
The training packages say something like "normal plus d10 (open ended)." In such a case, you would roll a d10 and add that much in silver pieces to your normal starting money, continuing to roll and add so long as you get "10s."
Any money rolls you take as Background Options are in addition to the regular starting money. Yes, you can get very lucky and start with some serious $$$.
The alternate Wealth rules in Character Law replace the 2 GP/20 SP in favor of a random amount that is determined by your character's wealth level and a roll. The first roll is "free" and has a modifier depending upon the wealth level. Again, you can come away with some serious money, but it looks like, even the Very Poor under that system will never have less than 25 SP (or 2.5 GP) of starting money with that system. Also, a "Very Poor" person could walk away with a 1 PP (read: 100 SP) jewel. Not sure about that.