Hi Tony,
I own a 2x barlow which i bought from bintel (most likely the same as the gso)for $40 and it works great with my 10mm super plosoll from andrews but i have a 6.5 mm ep from andrews aswell and works allright but i'd go with better quality eps if you have the cash.
i want good quality eps but i'm only 14 yrs old and can not afford them so the gso ones are cheap.I'd say get the 2x barlow its good.i'm thinking of getting one of andrews wide fields as i use low power most of the time when not viewing planets.
orestis
ps-what telescope are you going to use it with?