Sherri Hill, Blush Prom, LaFemme, and Jasz Couture dresses for cheaper prices?

I am looking for these Sherri Hill dresses:
#7208 Strapless Peacock Princess Ball Gown
#9204 Backless Graphic Print Prom Gown with Train (this one comes in different prints that have different style numbers and are different prices)
#3400 Sweetheart Babydoll Prom Mini with Rosettes
#2223 Rose Romance Ball Gown in Tulle & Lace

These by Blush Prom by Alexia:
#9048 BWT Barbie dress with huge BLK polka dots and 5-tier assymetric ruffle hem
#9005 Purple/Ivory V-neck gown with dramatic beaded T-back
#9047 BWT ballgown with floral one-shoulder and gingham inset and heavily ruffled skirt
#9083 Short irridescent taffeta with beaded-bra and rosette-hem

Jasz Couture:
#1644
#3103

LaFemme:
#12182

I would like to know if there are any cheaper prices on these dresses, or other dresses by the designers. And if there are any dicounts for shops (online or not) that carry these designers.
Thanks so much!