A good ground blind is constructed out of natural materials, utilizing the terrain around where you hunt. Without knowing where you are hunting and what is in the general area, there is no way for sure to answer your question.

If it was at the edge of a farmers field, I would purchase some hay bales and sit between them - deer are not afraid of hay bales in a field.

In the woods, I would stack up some logs - like a log house and put some brush in front of the blind.