price field. A MARKET order says "fill me now at the best available price", so a price makes no sense. Sending one is rejected outright, not ignored.SELL reserves the base coin, so this example needs 0.001 BTC available in your spot wallet. A MARKET BUY reserves the quote coin plus a slippage buffer, because the final cost is not known in advance.GET /v1/market/depth first. A MARKET order pays the spread, and on a thin book that can be far more than the last traded price suggests.price comes back as null and timeInForce comes back as null. Read avgPrice once the order fills to see what you actually got.