The more free listings available, the more likely that your competitors will list stuff at a lower price than you. Especially newbies with no idea of the actual cost of doing business here.
If you list 50 or more unique items, it is worthwhile looking into the cost/benefit of opening a Store where FVF are lower and there are more free listings.
If you can't make money when your listing costs you 30 cents a month, then it is time to rethink your business plan.