Hi Rose!
Thank you for bringing your question to the Disney Parks Moms Panel. The runDisney Health & Fitness Expo certainly offers opportunities to purchase a plethora of commemorative items to celebrate your accomplishment!
If you are certain that you would like a commemorative item, I would go online and purchase it before hand. You can do this after registration, but before the event. If you to to
runDisney.com and under events click on your weekend, then the Registration tab. If items are still available you should see a link under 'More Magical Registration' that should take you over to Active to purchase the item. If they are sold out for pre-registration, runDisney will usually have additional items for sale during the expo. These are in very limited quantity though and do tend to sell out. If you cannot pre-purchase, I'd recommend attending the runDisney Health & Fitness Expo as early in your trip as you can to give you the greatest chance of availability.
From my personal experience, I prefer staying at one of the
Walt Disney World Resort hotels on property and I recommend this to friends attending races all the time! The morning of the race can always be a little hectic and on top of the
great benefits of staying on property, I think the race transportation the morning of can't be beat! Traffic can back up because of the road closures for the race, but in my experience the runDisney transportation has a dedicated lane to the race location so you don't have to worry about getting stuck and missing your corral.
Please let me know if you have any other questions and I'm sending pixie dust your way for a magical race!
-Lindsey