Hi

If you have a look on the private apartments to rent you will find a few apartments for rent also I have sent you a pm

Balkan Holidays, the market leader, do plenty of apartments HERE

You are better with a package holiday because then you can be sure that the flight timings fit the apartment availability and transfers are included. You also know exactly what you are getting and are protected by the Package Holiday Regs if things don't turn out as you were promised.

As for location there is a map of Sunny Beach HERE, or ask on a name because I'm sure one of us will know.

It's warm/hot enough up to the middle of September normally.

Peter

I would agree that Balkan Holidays are very good, Royal Dreams and Sunny Dreams are very nice apartments, but i would not rule our booking your own flights and apartments, we have had people renting out our apartments so has a number of friends of ours we also book the taxi for them and we have had no complaints so far. But it all depends if you want a package holiday or your want DIY hope you find what you are looking for :
ps. the weather is unpredictable in September so take a warm cardigan for the evenings just in case especially towards the end of September