Many thanks! Had a quick look for you and, as you say, most APIs want payment for "business use", even if it is only one or two feeds.
Found that Binance has a public price feed. Have not researched it any deeper, but look at this link: https://api.binance.com/api/v1/ticker/price?symbol=STEEMBTC
Here are all their ticker codes: https://api.binance.com/api/v1/ticker/allPrices
Only STEEMBTC, ETH and BNB.
Hope that helps a bit.