Another vote for "don't bother with cheap card stock". I too thought I could save pennies by buying cardstock from other places, but realized very quickly that it was a waste of money. I would rather use SU. If for some reason you want to try out a new fold or something prior to using SU card stock, just use copy paper or something.
I know this really isn't the answer you were looking for, but I am die hard SU card stock user and won't use anything else.