Yes some combanies offer free samples for some antibodies like cell siganlling,abcam...etc...you can contact customer services directly and ask for the desired one..Good Luck.
Doaa Yamani is right. I had asked for free sample antibodies for my work from Abcam and they had provided me with a few microliters. So, you may go ahead and request for free samples. I am sure some companies may provide you with free antibody sample.