30-50 gallon aquarium tank (Katy gate)

Hi everyone!
My 10-year-old son is super excited about setting up his aquarium project. We currently have an Oscar fish pair that is growing fast, so we’re looking to upgrade to a 30 to 50 gallon glass tank to give it the space it needs.
It doesn't need to be fancy—just water-tight and in decent shape. If you have an old tank sitting in your garage or basement that needs a good home, we would love to take it off your hands and can pick it up at your convenience.
Thanks so much in advance!