Hi Chayce!
I think that in this day and age, most party goers appreciate a little direction in knowing what your little one wants or needs! How exciting that for your son's birthday you want to give him his First Trip To Walt Disney World!
I think your best bet would be to let your relatives, good friends and son's friends' parents know what you're planning for him, and to steer them in the direction of Disney Gift Cards. Consider something like
"in lieu of gifts, we'd greatly appreciate you being a part of the gift we're planning for our son - a Magical Walt Disney World vacation! Disney Gift cards would be fantastic and put towards (your son's) First Ever Trip to Walt Disney World! Thanks for sharing in our excitement over these plans!" You can then include a slip with the Disney Store website listed, or, if sending the invitations electronically, include the link in the evite (I've provided it just below for you).
You can receive many of these cards, and then apply those by phone towards your Magic Your Way Vacation balance, use them to purchase Park Tickets or even let your son use some in the Parks for souvenirs of his magical vacation! Don't worry about having too many cards received, Cast Members are patient and will be most pleased to assist you in processing them by phone for payment as you wish, or in the parks.
Disney gift cards can be purchased online at the
Disney Store as well as in Disney Store retail locations around the USA. There's a variety of fun card designs to choose from now which makes them extra fun to collect, re-load and re-use!
Wishing you a Magical time as you plan for your son's birthday and Walt Disney World vacation Chayce!
Kirsten