When the money runs out, the flat building seems to be the first to go. I love a Designer that really thinks out of the box. More than that, I love Producer who thinks out of the box. When there's no more money, creativity oozes from these people. They have great ideas and I love working with them. Designing awesome from nothing is the greatest challenge of all.
When there's no more money, there's often no more Location budget, and a Studio that can possibly be utilized more.
A Producer asked me once to design the back of the sets to be set walls. The effect was surprising. There was such an interesting feel to the ad-hoc set, that was fitting for the show. I don't think I could have designed such a set had I tried to think it up on my own. The nooks and crannies that occurred from the jacks, the strange irregular wall form that established the new set were so odd and bizarre: the Set had a fantastic sense of depth.
Another great idea that came from limited funds was to use a combination of cheaper materials, eg corrugate and fabric panels, and to combine them with lighting techniques. Custom Gobos excite me for this reason. A bland corrugate wall comes alive with wildfire paint or gobo patterns. It can be tricky to design a set based on lighting because of the action creating shadow. Its part of the challenge, and it can look incredible. The colours are fresh. The look is fresh. We're all happy to see something other than flats.
The sets always turn out awesome. Because they are extremely creative. Of course, it depends on the set you are designing, and the nature of the show. Some sets demand flats, and there's just no other way.
Thats when the Production Office turns into the set!