That's rust and oak tannin stains.

Stainless appliances on sale at big box.1 inch vinyl blinds from big box.Mahogany flame stain on decks.

If you ask the homeowner to fix a stain in the carpet that was found on the inspection, they can just say no and the buyer has the option of cancelling the contract under the inspection contingency, or waiving that item. 

Improvements and costs: repainted everything ($1k); removed carpet in bedrooms and hall and replaced with 25-year LVT ($2k), which required floor leveling; replaced kitchen formica with granite ($1k); professionally recoated very stained cast iron bathtub and tile surround ($1k); repaired kitchen cabs, painted and new handles ($800); new stove hood ($50); replaced old light fixtures ($100); replaced bath vanity and mirror ($250); new toilet seat ($20), new blinds in living room ($100).  

The cabinets in the kitchen and bath had to be cleaned to get the brown stain and stink off too.Just scrub everything and then seal paintable surfaces with Kilz pet odor paint.

Stains that cannot be cleaned out or ripped carpet would not be normal. 

Concrete or pavers would be low maintenance, but you can still get 20+ years out of a pressure treated deck if stained and sealed regularly. 

Stain/Fix the deck, landscaping, put a nice Faux stone front porch.  

The kitchen has good solid cabinets that will get a coat of paint or gel stain and new laminate tops.

If it's stain grade I'd go with a cherry, which is also a dark brown.