What is the best way to generate excitement for you party? Send your guests an invitation that will peak their interest and get them excited about what's to come!
Our idea here was to print out an invitation with all the important information for our party, and cut it in the shape of a hang tag.
Using a safety pin and thin piece of ribbon, we attached the tag invitation to a plain white t-shirt that the guest will bring with them to tie dye at the party.

These invitations can either be hand delivered or sent in a mailer package via USPS.
Though it would be less of a cost for you to ask guests to bring a white t-shirt, rather than provide one, if you can add the extra touch to this invite, go for it.
The kids will get that much more psyched for the party. Plus, packages of tees are pretty affordable!
Resource
Printable invitation by DIY Party Designs