I am a member of Phi Theta Kappa at my school. There are many benefits to the honor society, and being a member can be beneficial in many ways.
First, there are a lot of schools that offer transfer scholarships
when transferring to a four year institution. Next, there are many additional scholarships that are only available to Phi Theta Kappa members. Also, they will write letters of recommendation to schools as well as employers. A letter of recommendation from an academic honor society looks good. Additionally, the organization offers you an opportunity to perform community service projects. Finally, once you are a member there is a stamp of "Phi Theta Kappa" on your transcript. These are just to name a few. A $75 fee to gain access to $1,000's of dollars in scholarships, letters of recommendation, and the prestige of being a member of a international honor society is well worth it.
Some will say that it isn't really that big of a deal. However, it speaks volumes on your work ethic, discipline, ability to accomplish a task set before you, your teachability, as well as your ability to excel.
You should consider anything that will set you apart from those that your are competing with.