If pump

[CrazyEyes]

Looking for something I can run externally for a water change station, looking for something cheap like a mag 3 would be perfect.

 

[matthewduren]

John @ ichthy stuff had some external pumps for $50 on his as is used shelf when I was there earlier, might be a little bigger than you're looking for though.

 

[Rustafar]

Try Harbor Freight. They have some that I've used for over a year and still going. https://www.harborfreight.com/catalogsearch/result/index/?dir=asc&order=Sort+Price,t&q=water+pumps