I've never been to a game that wasn't table stakes. I thought that went out in the 1970s.
You really have to set a capped buy-in and ONLY PLAY TABLE STAKES.
If you want to have a very different type of chip, consider getting the European poker chip
plaques. Perhaps you could use these to represent $10 or $25. They are square and should be easily recognizable to your color-blind friend. You would want to get plaques without dollar amounts on them, of course [img]/images/graemlins/smile.gif[/img]