Which is the best deal?

Personally, I would go with the 75g. They're the same lenth as the 40&55g tanks, just a little deeper front to back. If you're worried about the cost of gravel you can always go to someplace like Home Depot or Lowe's and buy pea stone(50# bag = $3). It's a good price and you'd really only need 2 bags at most.
 
Another good source are thrift stores. If you buy a tank there though, or any empty tank I think, be sure to reseal it.
 
When resealing, do you put the sealer inside the tank, outside the tank, or both?
 
Hey Daisy, I didn't notice till I got back to this thread. But, I gave you some instructions in your other thread (it turns out...) about resealing a tank. Take a look there and you should have no problems, it's pretty easy. Once again, good luck and have fun.
 
So good to hear there are young people keeping fish in a responsible way. Good for you guys/gals!!!

You can also ask friends and neighbors. I just happened to be at my mom's house (I am 39 however) telling her about wanting a bigger tank and then my sis & bro in law came over. I told them I was there looking to see if mom had any old tanks in the garage (my dad kept fish for years) and they said they had a 20g w/filter, gravel and heater they were getting rid of. I am getting it all for free. I know I will have to do some things to the filter and get some other supplies. But it sure will save me money

Good luck and happy fish!! :D
 
Good plan. My neighbor has kept fish for years and quit the hobby when all his fish died, but he would make me pay a lot of money for it!
 
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