Here are a few sites that sell the replica coins:
http://www.windycitynovelties.com/EPaysoft/Cart/product.asp?ITEM_ID=13968&CatID=0
http://www.skybluepink.com/global.html
http://www.mamasminerals.com/page/MM/PROD/BEC-CHIN3
http://www.articusstudiodesign.com/id71.html
While there are zillions of actual Chinese Cash Coins out there being found and dug, there are also these replicas almost everyplace. The grainy back ground and clear crisp condition is a dead giveaway... often sold in packs with other coins.
See this recent post better explaining the replicas against an authentic coin:
http://forum.treasurenet.com/index.php/topic,167917.0.html
An actual
Ch'ien Lung T'ung Pao coin is common, in fact, is the most common standard cash in the history of the Chinese coinage. Making even the actual coin, unfortunately, almost valueless. Check this ebay listing of 40 coins from the dynasty - priced at just under $30.00 with shipping.
http://cgi.ebay.com/40-Pcs-Ching-Dy...VQQcmdZViewItemQQ_trksidZp1638Q2em118Q2el1247
Hopefully this helps... if you are not comfortable with my comments please by all means have it checked out...