A big part of some shows is The Hunt - the search for the right furniture or architectural details. If the play is set in a historic period, ordinary contemporary doors or furniture just won't work - not as-is - so you have to find real or seeming antique styles for... everything. This hunt is complicated by the limits of a theatrical budget.
For In the Other Room, we need to suggest the late 1800s. So the whole design team is huntin'; yesterday the builders and I went to the local Habitat for Humanity resale shop, the Restore - a fantastic resource! - where new and used building supplies are sold for less than retail prices.
Middling success. We found great new, but old-fashioned, doors - but they still cost too much, so we decided on plain flat-slab doors for only $5 each, to which we'll add molding to suggest two-panel doors. We found inexpensive brass and china handles to use in building the machine. But no luck on a period light fixture. (I'll go back to see if anything new comes in next week.)
Afterwards I hit thrift shops and found 2/3 of the weather vane I'm going to cobble together; I still need a metal bird. More thrift stores today! When possible, it's good to shop first at thrift stores that support non-profit charities: for one thing, they have the odd, used, random things a theater set needs, for another, your theater's money is used to support another non-profit and a worthy cause.
Oh! And shop with a car or truck that can carry your finds. We almost had to strap those doors on a car roof, but managed to cram them (mostly) into another vehicle, tied in place with computer cable!