How much tax will I pay when I sell the house I have lived in for 30 years?

Thirty years of ownership usually means meaningful appreciation, so your federal capital gains exposure depends on your original purchase price, any improvements made along the way, and today's sale price, offset by the primary-residence exclusion the tax code provides if you qualify. Georgia's transfer tax also applies at closing regardless of gain. A CPA can calculate the specific number for your situation rather than an estimate.