The ones that obstruct a trash can usually are toy quality, as are most of the under-$100 dedicated ones. (Toy, as in "can't shred one year of old tax returns and backup papers without extensive cool-down periods.") But I think the folks at LifeLock are giving one away free with a trial
membership, you might want to look them up for that.
If you only need light use...there is something to be said for the funky scissor and then just burning it.