Etsy.com

eBay.com

Allposters.com

One of my favorite places is in Gettysburg, PA. They are also online and the owner of the gallery is just fantastic, he has a Lab that goes to work with him many days and she "writes" an entertaining article in the newsletter. We have bought a few things, my favorite is the canvas print we have of Anna of the Celts (Dean Morrissey), I just love it. Also some of the ones by John Weiss I really enjoy.

I have ordered a couple things for presents for my husband and as farewell gifts for some of his soldiers and they shipped quickly and I had no issues, prints were well packed.

The giclee prints are usually up there in price but the prints on paper are reasonably priced and the owner is very knowledgeable so if you have a question before buying or want advice as to what may increase in value, etc, just give him a call.

Here is a link that might be useful: Lord Nelsons Gallery

Overstock.com, 20x200.com, greatbigcanvas.com

Etsy for sure! Just be prepared to spend a lot of time looking, there is so much wonderful art on their site.