Enter the Tote Bag! When you hand over your race swag in a custom tote bag, your participants know that you've stepped up your game. Participants love it, and they'll be used throughout the year at grocery stores, beaches, and everywhere in between.
Sure, the cost is more than a plain bag, but having a custom tote bag for your race doesn't have to cost you a penny. This is also an excellent sponsorship opportunity. I generally price my race tote bags with two sponsors, where the combined sponsorship revenue covers the cost. Cost is covered, and you look like a champ providing this as extra race swag to your participants.
Pictured on this post is this tote bag. I've also purchased tote bags from Inkhead.com. You'll see that both have a huge variety of tote bags at different prices, and I'm sure your favorite screen printer can do something similar. They also constantly push out promo codes, especially around the holidays. So, I'll generally wait for a good 15-20% off promo code, and then order my bags.
In the end, my out-of-pocket cost is zero, sponsors are happy, and participants are happy. Plus, your race participants can promote your race all season long.