Obviously you've made your choice...but here's my humble opinion for the future.
It depends on your situation...if you're buying a tank that you know is going to be in good condition or will just take a little work or time to set right, why not. Like Seraph said, we got a 60 gallon acrylic for $50, sure we buffed out some light scratches, but it's a fine sturdy tank.
If you're looking a 100 bucks between new and used, go for the new...no question, it's just not worth it. We're building our stand b/c we wanted a very specific look to it.
It all depends on your situation and what you want out of it. In no way shape or form would I call what's sold on ebay or any other of those sites junk...and with enough time and effort on your part you can make a gem out of just about anything. So that being said it's also about how much time pre-set water and fish you're willing to put into your tank in and of itself.
that's just my opinion though.
Happy filtering!