I bought this one at Amazon in 2007, use it at least an hour a week, and it is still as good as new.
http://www.amazon.com/Elite-Molded-Roller-Round-Popular/dp/B000HLLREA
geeyoupee linked his about six posts down. I went with this one five years ago and it is still good as new:
http://www.amazon.com/Elite-Molded-Roller-Round-Popular/dp/B000HLLREA
I'm sure both are fine, but his point is a good one - there is a big difference in quality between the $15 and $30 versions.