It is not extorting money for the person to “suggest” giving something to tzedaka. It kind of IS, though, when the giving of the chessed item becomes contingent on a specific dollar amount being donated. To some people $75 is a lotta gelt.
I have given away many items over the years, including clothing, a breakfront, chairs, tables, bicycles, cribs, and other baby items. I would be thrilled to know that someone gave money to tzedaka in that zechus, but I would never have mentioned a word about doing so, to the person. It puts them in a very awkward position.