A few tips please

As we are first timers to Icmeler I have a few questions wondering if any one can help. I think I have read most of the posts on this site and have noticed that some mention taking extentsion leads, Is this just for self catering or in hotels? We are staying in the Marmaris Park. We are travelling from Birmingham 25th Sept have read lots of comments about luggage allowance just wondering if its worth buying toiletries airside after cases have been booked in and taking them as hand luggage.(anything to take that extra pair of shoes) Also is it cheaper to buy a beach towel when we get there or I think I have read somewhere that you can hire them.
Any advice will be great.
