So your not sure if you should hire a professional wedding planner or just ask a friend to help out at the reception.
Well it might depend on what you need help on, the days logistics and which friend.
If you are going to ask a gal pal, make sure she is organized and know that you might be keeping her from the party. But there could be some things that a friend could help out with:
If you are looking for someone to make sure you have everything to get ready, be there to help put the dress on, put your purse together and give the BM the rings(ie: a bridesmaid).
make sure the photographer has your must take photos list.
set out your homemade centerpieces.
If you want someone to truly manage your day, work with your vendors, act on your behalf and make sure all your friends and family are having fun you need to consider hiring a professional. A professional will be your eyes and ears, be knowledgeable of what you want, be familiar with the wedding professionals you hired (and what the contracts say), help you make decisions and will know about timing issues that could affect food and catering.
If your day of planner is good he/she will start working with you about a month from the wedding. They will go over your plans, review contracts, make a timeline, contact all your wedding vendors, answer your unending last minute questions, talk you through your seating arrangements, your ceremony programs and your must play dance songs - all BEFORE the actual wedding.
They will coordinate the rehearsal, ceremony and of course be there on your big day to make sure all your plans are carried out. Remember they are working for you on your behalf, not the hotel or catering facility. Their #1 priority is making sure your day is wonderful and all issues are dealt with behind the scenes.
Coordinators fees range but remember you get what you pay for. The expenditure might seem like more then you want to pay but can you put a price on peace of mind? Let your friends or aunts enjoy themselves, party with you on the dance floor and leave the logistics to the professionals.