I've seen some devs do this as well, but just the ones that it's feasible for.
I don't think this is a feasible option for a small dev like myself.
I buy quite a few keys from small indie developers here. Maybe the phrase “free keys” bothers you? I mean, I only buy the games here for that reason and pay the full price for them.
You can DM me on my Discord and I'll try to help with this
