The hardest part of organizing a PTA fundraising idea is at the beginning, when you are assessing needs and searching for a PTA fundraiser idea. The fun part comes later, when you get the ball rolling and start seeing some results, but don't get too far ahead of yourself, because there's still some work to do first. You need to think about the size of your team, how many volunteers you're likely to have, and how much money you need to raise in total. If the PTA has an existing funds stash they can use as investment money, you could go for something like a direct sale PTA fundraiser, like fundraising scratch cards or pizza discount cards. This sort of card-based PTA fundraiser is great for profit, as you can make up to 90% depending on how many cards you can commit to buying upfront.
A PTA fundraiser can be a lot of fun, but don't underestimate the work involved. It's important to bring this up at a meeting as soon as possible, so that everyone is on the same page with regard to what is expected of them and what will have to be done in order to reach the PTA fundraiser monetary goals. With a strong foundation of organization, you've already taken the biggest step toward a successful PTA fundraiser.