Actually, got the answer from their website:
Buying agents get paid 2.5% of the purchase price, which means on a typical $2 million single-family home, they get $50,000. Given escalating Bay Area real estate prices, that didn’t feel right to us, so we rebate 2% of the purchase price back to the buyer (subject to a minimum commission of $12,500 to Unlocked). If the buying agent commission is less than 2.5%, we reduce the cash back rebate by the same amount. For example, if the seller is only offering a 2.25% buying agent commission, you’d receive a 1.75% cash back rebate. If Unlocked would earn less than $12,500 commission, we rebate you all of the buying agent’s commission, after deducting $12,500 for Unlocked to cover our time and expenses.
I have used someone who charges less than this:
https://shopprop.com/services-calculation.html
ShopProp charges a minimum of $2k and a maximum of $6k compared to Unlocked’s minimum of $12.5k
Caveat added later: when I used ShopProp is 2018, their minimum commission was higher. I recall $6k min and $7k max. And the website now seems broken - missing logo etc. That wasn’t the case in 2018. So, not sure what’s going on there. If anyone decides to go with ShopProp, please know that I personally used them in 2018 but if I had to use them again, I’ll do due diligence again because of the changes mentioned above.