Whoa, I don't remember the AquaDurt being that expensive last time I looked. At that price it would be cheaper to go with Flourite Black or Dark, the latter which I really like the look of:
Very natural. Not my pic, it's from this thread which also has some close-ups:
Seachem Flourite Dark, Experience and Pictures
Got it for $16.13 per 15.4lb. bag from That Fish Place, with free shipping and 10% off coupon.