Hello, retirement here in Sri Lanka is good. The best route for a retired person is to apply for the 'My Dream Home' retirement visa. You need to be able to demonstrate that you can bring in $USA 15000, which is returnable should you leave and is in a fixed rate deposit accoybt during your stay, and a monthly remittance of $USA 1500. Go to the Sri Lankan Department of Immigration and Emigration website for full details. The cost is approximately Rs40,40,000/= for a 2 year residence visa plus charges and taxes. The Dept has an official agency at 330 Galle Road, Colombo 03, not far from Liberty Plaza and they are extremely helpful and you avoid the necessity of going to a busy, busy building by using them. The visa foes not allow you to work etc.
If you want to purchase a property get a very good lawyer and use a reputable property agent. Leading is probably best though.
I came over initially for six months and rented to help me get a feel for the place etc before I committed myself.
Hope that helps?