Little to none. If they own the property, and not you they have the rights. Your choices in this case are going to be what they are presenting to you, start paying rent or move out. Unfortunately the past 7-8 years of them allowing you to live there don't entitle you to any legal claim to the property, it was their choice to let you live there rent free, and now they are choosing otherwise.

AC

If you think that you have some rights to the property then you should check with an attorney and ask them about your rights under Adverse Possession.  The concept is straithgforward but how it is applied in each state differs.