I'm not sure if they have trades days like they do in East Texas, but I was able to find all kinds of crazy stuff that looked like laboratory equipment and old computers. I started collecting mannequins and any size especially large (36 inch) saw blades. It was a lot of work detailing these peices but all for probably under $450 that became several rooms tied together.
Last year the event coordinator said they wouldn't be using my lab scene or saw blade room this last year and did I have an idea for 2 rooms? 2 weeks before opening I said how about a saw blad room and a laboratory?
I ended up over time cutting power cords off of any junk appliance I could find and in the lab I had hundreds of exposed wires and cords hanging with electrical sound effects like some might be live. It was not as dense but similar to a tube room that had to be negotiated.
There ya go a tube room isn't that expensive. Any old duct work and large tubing and lots of aluminum foil makes a cool boiler room.
Jail cells made out of electrical conduit and some PVC.
Used office furniture becomes the doctors office, you can go to second hand office supply stores and buy what is so crappy they haven't been able to sell for 5 years and get things dirt cheap. File cabinets labeled for poison, list of who to poison, recipies for poisons and so on.
Perhaps rare in your area but fill rooms full of cut off trees. Either plain or white with colored light in low light looks cool.
Cemetaries need not be super detailed if the lights are low it can just be styrofoam (white) not even painted or marked in any way just cut out giving the impression of a cemetary.
It is tough to come up with furniture that hasn't already been in a crack house or is priced like louis the 5th himself sat on it once.
Contact local colleges for old charts of chemicals and even human anatomy, it need not be in pristeen shape, you might get to clean out a few closets with microscopes that don't work and such.
Luclily I get to drive through neighborhoods and have actually seen cool finds being set out for trash. I always knock on the door and make sure I can take it rather than just be a garbage man. In a way, you see something and then figure out what can be done with it. Patio furniture lounges become a skeleton tanning etc. One year someone threw out a sunglass display so every creature, prop and monster had sunglasses.
You would be suprised what you can find with a few thousand dollars and a mission. If you have as many actors as you have scenes it all adds together to be something.
The big thing is it can all be junk, never has to function and even having a corner knocked off is fine. Tables with only 2 legs get bolted to a wall or distressing need not be done or can be enhanced. Places where a chunk is out gets enhanced to be large monster teeth marks with a grinder in seconds.
Another fabulous post from the U.S.Department of Wild Imaginings, now in spectaclar stereo, sponsored by the Adhesives and Sealants Council, suggesting ways to stick things together since the 1800s. Not fabulous in a gay way. Your results may vary. Illinois residents add 8% sales tax. These posts have been made by professional post makers, do not try this type of posting on your own without extensive training, lovely assistants and a trusty clown horn.