The smallest store of value chip in my sets is 20x or 25x. I prefer 100x. So for a $0.25/$0.25 game a $25 chip.
Why? I don't want anyone ever betting with a store of value chip. The only chip ever seen in the pot is the betting chip. In this case a quarter. Sure as rain on a 4th of July parade, when the host puts a $5 chip in play as a store of value chip, ten minutes later someone puts a $5 chip in the pot to call a $1.25 bet.
Been there, done that and now I try not to do it again -=- DrStrange