You can pay $500-700 for a name brand panel. No doubt they are very good and 4 different middle men took a cut to get it there. You can go on the internet and get something on E-Bay that might... or might not work. When I installed my system I went on the net, took a good close look at the images and specs, read a few user blog post, and picked out panels that were solid and are still working well. But I've heard stories of the other sort.
Hotwire is a guy that started investigating solar and wind for hi own use 20 years ago, tried everything, tested samples, and has made a solid little name for himself among cruisers as a guy that sells right-priced stuff that he has tested and vetted himself.
But it's a lot more than that. Wind, charge controllers, mounts, lighting, refrigeration... all with an eye towards economy and reliability.
Check it out.