Corns love the inside tubes from toilet rolls (hatchlings) or kitchen roll, cut in half lengthways. Also cereal boxes or similar (with one of the larger sides cut off so you can just lift them up to find the snake). Free disposable hides! I also raid my local dollar store (UK equivalent) in the spring for papier mache hanging basket liners. Cut a hole in them and turn them upside down for more lightweight, cheap hides. For more robust hides I use earthenware flowerpots turned upside-down, with the drainage hole enlarged (remember to make it the same size as a freshly-fed snake though - you don't want the embarrassing visit to the vet that I once had with my Pumpkin...).
Plastic lidded tubs with a hole cut in the top or side, are perfect for humid hides or laying boxes if you breed. A few of mine arrived in my house as cookie containers, or again, you can raid the dollar store.
My garden centre supplies horticultural grade vermiculite for humid hide or laying box substrate and my local hobby shop stocks cheap plastic foliage (supposed to be for permanent floral arrangements but they make great ground cover in a tank and are cheaper than "proper" reptile ones - you just have to make sure there are no sharp wire ends sticking out)
Water dishes are again larger plastic tubs - rectangular ones when full seem much more difficult to barge about than round containers. The more active of my gang have big ceramic dog bowls for their water. No chance of the snakes shifting those.
To carry snakes around outside the house, I first put them in pillowcases and tie the top with a shoelace. I then put the pillowcase+snake in an escape-proof plastic travel tank and pad/insulate it with old towels before putting the lid on.
