There are lots of power supplies on eBay or amazon... I used a 3amp model that was $10 with shipping but you have lots of options.. since I use both 24v and 12v I now use a bigger 6a 24v power supply with a step down buck converter to make 12v from the 24v for the 12v stuff I still use on my electric brew control panel but no need to get that. Complicated.
You can find wall worts of power supplies for DC appliances at junk stores and thrift shops or even use an old PC power supply.... I also used a pwm DC motor speed control unit which range from like 3 to $10 each... these enable you to daily in an exact speed if needed.... ball valves will still work as long as you use them in line after the pump. I chose to not go that route though.
I should add that their are you tube videos of these pumps in action...
https://www.youtube.com/watch?v=suv3vqGnoFg
https://www.youtube.com/watch?v=artHgfhYkxw
https://www.youtube.com/watch?v=UPUtPO2qI9s