Whooooa there.
Chris/Eurotimez sells a basic Noobmariner for 120$. For 40$ more you get the upgrade for a 4813 movement, which is a 28,8k high beat and has a much smoother sweep:
http://www.rwg.cc/members/index.php?showtopic=82237
Then, he sells other models, such as the Euromariner, which are more expensive.
And to answer your question, it is all about supply and demand. The Submariner is probably the world's best known and most wanted watches. Hence, it is one of the most and best replicated.