The Steelcase Leap is my personal favorite office chair of all time, but it retails for around $1,000.00. You can sometimes find them for cheaper if a company gets liquidated and is offloading their old equipment.
I regularly find refurbished liquidated Steelcase Leap v2 chairs in the Bay Area for between $250-350. Find a set of gel wheels on Amazon for $25 to replace the plastic casters and you've got a great chair. There's actually a used chair store right next to YC HQ in Mountain View.
That said, these days I slightly prefer the much cheaper Ikea Markus with the arm rests removed and angled at approx 135 deg.
