Hi _]im
It sounds expensive to me.
I just checked and $70 Canadian comes out to about #55.50 US. I can get a new 10 gallon starter kit which includes incandescent lights, an air pump and box filter, gravel, and a few other odds and ends for less than $30. For $55 I could get new everything (except the stand) in a better quality.
The unknown factor with this deal is the stand. If you need it and if it's very nice, it might make a difference.
When buying used equipment I never count the heater because it is fragile and there is a good chance it might not work. A new 10 gallon tank costs me $8 and is the cheapest part of a set up. If the gravel is anything but natural rock I wouldn't count that either, (used gravel is a pain to clean) and if the decorations are anything I might not use, I wouldn't add them to the value of the set up either.
Why not call around to your lfs and see what the lights and filter cost new and consider that the most important part of the deal. Add what you think the stand is worth to you, and the cost of a new 10 gallon tank, and see how it looks to you then. If it's still a bargain, go for it. If not, watch yard sales and the like and you might do better.