My concern for your situation is that any search engine optimization would be of marginal use, give your site's subject matter. You have to ask yourself:

1) Who is my target?
2) What are they looking for online?
3) How would they search for it?
4) Who is competing for that attention?
5) What is more compelling about my website?

You seem to answer the question about your target in the opening paragraph of your website: ebay and flea market sellers. Well, a website seems like an awfully round-about way to reach these people when you've done such a fine job of drilling town to specifics.

If I were in your shoes, I'd jump on eBay and sprint to the nearest flea market and start shaking hands and kissing babies. Hand out your URL to those specific people, and your ROI will be a hundredfold what a little bit of search engine optimization will get you.

Hope this helps!