The majority of closing costs on the buyer's side of a transaction are associated with the cost of obtaining the loan so when you are not using a loan, your closing costs are very minimal. It does depend on which title company is closing the transaciton and what their fees are but the only closing costs you should incur are the cost for the title company to conduct the closing (referred to as closing or settlement fee) and the cost for them to record the deed on public record (very minimal - should be under $50) I would say a good estimate would be well under $500.
If you own a home free and clear, you are not required to carry home insurance although it would be wise to do so. Property insurance rates vary depending on deductibles, location, etc. Try http://www.shopandcomparerates.com
Good luck in your home purchase. If I can be of any assistance, call me any time on my cell at 727-541-3743.
Darla Schroeder, Realtor, GRI, e-PRO
Century 21 Real Estate Champions
4350 Duhme Rd
Madeira Beach, FL 33708