I don't recommend you place too much value on the numbers you find on eBay.. If you need a valuation- contact a broker that sells that property and ask for a written estimate of value for your ownership. Most will charge you for a CMA (probably around $50).
If they offer to verbally tell you what it's worth and try to list you- be sure to find out what they expect to receive as a commission. You are better off getting a true valuation of what it would sell for, and a specific commission agreement that would come from that amount.
Don't pay for a valuation from a marketing site. Their numbers are based on advertised prices alone (not the actual selling prices)- and are generally unreliable.
You've already said you have ads on a number of classified type marketing sites. You may simply want to try lowering your asking price to ensure you are competitive with the lowest priced sellers on those sites.