The 10 gal. tank that your neighbor gave you , I take it was just the aquarium itself . What did he/she use it for ? If it was for fish then you will fine .But if he/she had small animals/reptiles in it , you will need to strip out all of the seals and re-seal the glass . The urine from the animals will soak into it and kill off your fish .
Learned this the hard way when I first started keeping fish .I was given a 20 gal. , bought all the accessories for it , stocked it and my fish kept dying off .I only asked the above question because I found out later that the people who gave the 20 gal. to me kept rats in it , this is why it had no equipment/accessories that came with it , and if I knew that before hand it would have saved me some fish and stress .