The FHA doesn’t have a minimum loan amount, but it is a mortgage insurer, not a mortgage lender. It insures loans made by lenders against borrower default. A lender may have a minimum loan amount. Shop around for lenders and find one willing to work with you.
The FHA appraisal process concerns not only the value of the property, but whether it meets minimum standards set forth by the Department of Housing and Urban Development (HUD) for safety and health. That may or may not be an issue for a low-cost home. Until any issues raised by the appraisal inspection are resolved, the loan is on hold.