I am possably getting a new 50 gallon and stand today, it comes with heater, gravel, filter, light... anything i should know, think of, little hints about buying used tanks?
I only bought 1 used tank, a 55 gallon and all of my other tanks I bought new. If you are going to buy a used tank I would recommend that you make sure that the tank is filled with water with all of the equitment operating. When I bought my 55 gallon tank the tank held water fine but the canister filter had a small hairline leak in it and water got all over the inside of the stand even though the leak was so small.
I tend to avoid used tanks as you never know how they have been treated.
Make sure you see it filled with water and if you use bleach to clean it out make sure you rinse it out REALLY well afterwards with just water, and then once it is rinsed out rinse it out again 2 or 3 more times
As mentioned check the seals. Make sure there are no cracks (obviously ) and make sure that there are no chips on the edges of the glass. While chips wont make it leak it does mean that it has been subject to some impact stress which might mean there are weak points in the glass that could give out later.