Based on the context and the answer, generate a question. 

Context: cheap online -pharmacy online cheap buy cheap generic generic viagra ! cheap online . Celebrex levitra nexium propecia renova valtrex viagra , generic cialis uk paypal viagra try before you buy viagra in canada tadalafil next day delivery no script .

Answer:

Because online pharmacies are often scams and people do not trust it .



Why might this advertisement suggest you to try it before buying ?