Coming up with DECA fundraising ideas is ofter the hardest part of getting the fundraiser off the ground, but since there are so many good fundraising activities available, there's a fun and useful way you can use the competitive spirit to have the most successful fundraiser ever.
Split your club members into two groups. You can either let people team up how they want, or draw names from a hat. Once you have your teams sorted out, give them a selection of DECA fundraising ideas, and let each team choose the idea they think they can do the best with (it's okay if they both choose the same idea).
Turn it into a fun contest, where each team stands to win a prize of some sort if they reach their goal before the other team does. You might also set up smaller individual prizes for the person who sells the most, or the person who gets to a certain sales level by a certain date.
You'll be shocked at just how well competition works for people with an entrepreneurial spirit. Encourage everyone to keep things sportsmanlike, and in addition to this being a great DECA fundraising idea, you'll also be helping the students to develop their teamwork skills and a healthy attitude toward competition.
There are plenty of great DECA fundraising ideas out there, so there's no reason you can't find plenty of good ones to suit your group and its needs. The rest is up to the students, and given their natural ability for sales and marketing, the sky is pretty much the limit for how well your fundraiser can do.