Buy/Sell REST API without orderbook?

Hi all,

there are some cryptoproviders out there that offer the option to buy and sell BTC (or other cryptos) not via an orderbook, but just with a very simple "purchase price" and "selling price". One of these providers is BISON, for example. There, you dont have to deal in any way with complicated orderbooks. They just tell you to which price you can buy or sell BTC (the company gains with the spread between buy and sell rate of course)

I have not found any provider that offers this simple option, but not only via website/app but also via REST API. All REST APIs I have seen only allow buying/selling via orderbook mechanism (i.e. setting buy/sell order, browsing orderbook for buy/sell offers etc).

Does anyone know a cryptprovider that offers buying and selling cryptos via REST API, but without order book? Just plain "Buy!" and "Sell!" for given price + amount?

Thank you