Poker is not really designed to be a "friendly" game. There are some games that have the potential to move a lot of money around. Such games aren't as much fun since they can result in one or more players being "cleaned out" in a single round, thus forcing them to spend more money or quit.
These rules largely prevent this by limiting the amount of money that can change hands in a single game (that is, a dealer can't pick a game that will clean you out). Obviously, you can make any rules you want but these are designedi, quite frankly, to limit what each player is risking in a single evening.
The goal of this game was to have everyone invest $20 (which we considered to be a small amount, but not insignificant) and be able to play for the entire evening on that initial investment. The specific values of the various colors were chosen because our particular collection of chips have almost twice as many white chips as any other color.
You can adapt this without too much work by simply changing the colors around so that whatever you have the most of is 50 cents and the second most common is 20 cents and so forth.
It greatly enhances the game of poker to be risking something. But it ruins it if you risk too much (the excitement turns to real fear). I recommend that you scale the game so that your group will feel the buy-in is significant but not burdensome. If you're all well off, maybe $200 would be more appropriate. If $20 is a lot to lose, make the buy-in $2 or even 20 cents. In each case (provided you always adjust the values by a factor of 10) you can still give out the same NUMBER of chips but the chips will be worth smaller or larger AMOUNTS (which, really, doesn't affect the game very much).
A Word About Values