"would you expense the $200 item but then depreciate everything else?"

It depends on the facts and circumstances.

"So you would separate items on the invoice."

Example: I run a water district. A bunch of $240 water meters + a $3,500 pump motor. Yes, I would separate these. But, a bunch of $240 water meters as part of a $300,000 system-wide improvement project = no, that would not be separated.

"Also, if this was for furniture, how would you deal with the installation fee or design fee?"

Example: Design fee + engineering fee + construction fee = the Building Costs. Furniture and the interior designer or decorator fee = the Furniture, Fitting and Equipment asset. Two different classes of assets.

"I was thinking you would add it to what you are depreciating if over $200 like Bill said. However, if there was an expense on the invoice for $100, i would need to allocate a portion of it pro-rata."

Again, it depends on what it is, why it is there, what it is associated with, how different it is from the other stuff, etc. Fencing is not the same as Furniture; these would be listed and tracked separately.