Welcome to BPNet!
Heck put the word out to friends, co-workers and family. You'll be surprised at how many people have used tanks sitting in some dusty corner of their basement that they'd love to unload on somebody LOL. Just remember every snake is a born escape artist so a secure lid, no matter what style of enclosure you have, is a must. On glass tanks, metal lid clips are your best friend.
As far as hides, no need to break your bank. Figure out how big the snake is coiled up, hit the dollar store and buy a couple of dark colored plastic bowls that are just big enough for your ball python to happily stuff itself into. Melt or cut out an entrance either in the "roof" or on the side. Instant hides for about $2.00. Sort of like this....
For a water dish you want something that's not easily spilled but is easy for you to scrub clean. Water dishes in the warm, humid environment of a bp home can be breeding grounds for nasty germs so you need a material that you can clean/disinfect easily. Personally I love these ramekins. Their kitchen grade and you can find them very reasonably priced in any major department store and some dollar stores in the kitchen supplies area.
As suggested above you do really need to address the issue of housing these snakes together. While it may not kill them to live together, the vast experience on this site seems to indicate that they do much better over the long haul by living solitary lives other than during their breeding cycles.