No disagreement with Hoss, just want to follow up on the liability issue, as that is likely the primary reason you might need AMA. If you have homeowner's or renter's insurance, you may already be covered for liability in some amount (read the policy/ask your agent to be sure). If so, you need to decide if the amount of coverage is sufficient for your comfort while flying model airplanes. If it isn't, the AMA insurance will cover a judgment against you for amounts in excess of your current coverage, up to $2 million.

Edit to add: You do not have to be at an AMA chartered club site for the insurance coverage to be effective. About half of AMA members do not belong to a club, so nothing out of the ordinary about your situation.

Abel