How can i build a small backyard pond on the cheap?

I have a TON of tadpoles that i rescued from a neighbors pool before it got torn down yesterday. Im currently keeping them in my fish tank with my one fish, which is a native creek chub. He may have eaten a few idk. So there are at least 100 tadpoles swimming around in my 10 gallon, so i obviously cant keep them... show more I have a TON of tadpoles that i rescued from a neighbors pool before it got torn down yesterday. Im currently keeping them in my fish tank with my one fish, which is a native creek chub. He may have eaten a few idk. So there are at least 100 tadpoles swimming around in my 10 gallon, so i obviously cant keep them there. I dont have hardly any money yo spend currently on a pro setup, but i do have a little for something. What can i do here? I dont wanna release them in the local waters as they are currently in VERY poor condition due to mine runoff.

I want to create a small safe space for them to grow and dont mind giving them a spot in my yard, plus i love the sounds frogs make especially at night. What kind of things would i need to invest in to create a small DIY yard pond, lets say no bigger than 4' x 4' at most. Also as i said my budget is VERY limited, so i could probably go as much as maybe $100 for now, later i can upgrade it, just not now. Anyone have any ideas? Help me help these little guys, their home was literally ripped away from them, i know i cant do much but id really love to do what i can for them. Thank you in advance.
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