That is a great way to market yourself.
Personally, I don't list for anyone else for two reasons: 1. Buying stuff for resale is easy. Opportunity is EVERYWHERE. 2. I've never had anyone totally satisfied with the transactions where I've listed for them.
For instance, a former friend had 2 packs of Polaroid film at her garage sale for 50 cents each. I educated her on it, and offered a 50/50 split after fees, which she gladly agreed. I got $40 per pack for that film, which was tip-top of the market, using my skills, time, packing materials and top rated status. For years after, you could tell that she thought I ripped her off. In retrospect, I should have paid the $1 for the film, and kept the profit all for myself.
I have a relative that is good as gold, and I agreed to list a trombone for him. We listed it as a BIN for $199, with no takers, so, with less than an hour left on the listing, I took a $185 best offer. The stupid trombone was really only worth $160 at best. To this day, my relative still thinks that I owe him the ebay fees and the extra $14, even though I spent hours finding a box for the item, and then shipping.
No good deed goes unpunished in any situation.