As of right now a GTX 960 4gb or R9 380 4gb will be your best bet for $200 but with the release of Pascal and Polaris this year there might be some price drops on some GPU's.
EVGA has a GTX 970 FTW+ for $249.99 that is "B stock". Still an excellent price for a 970 and performance is much better then that GTX 960 or R9 380.
http://www.evga.com/Products/Product.aspx?pn=04G-P4-3978-RX
"B-Stock Products are units which may have small scratches, small dents, or noticeable use. B-Stock products are Factory Recertified to meet the performance and reliability of a new product of the same model. B-Stock products do not come with any optional accessories and only include the accessories required to use the product as listed below."