Disclaimer: I have only played bedrock for a few weeks legit so Im not the most educated player this may already exist lol.
So for the Bedrock store it would be cool to have a option where you can post stuff for free. From what I understand you can post texture packs and such for people to buy for coins. I can say for sure a lot of people would be fine with just posting a resource pack or map for everyone to use. You shouldnt need money to get stuff like skins and texture packs. Not sure how to say this respectfully but the coin system is a disaster tbh. Having to pay from other peoples creations is just messed up.
There are plenty of online sites that offer that for the Bedrock Platforms (excluding Console as those dont really have a way of installing unconfirmed content). Even if there was an option for designers to post their content on the marketplace for no cost to the user, it would likely not be utilized, as the actual developer would have to cover the cost of the marketplace. What you need to understand is stuff on the marketplace is hosted and distributed by the platform its used on, and that all costs money. Even if designers and developers want to make their content free, most wouldn't or couldn't be able to afford those fees. This is why you can download them on your own from 3rd party sites that offer that option.