I'm would like to recruit executives and design leaders for a study, but my budget will only cover incentives. What are the best recruitment strategies that don't involve paying hefty service fees or yearly subscriptions?
Like Thomas said, do the recruiting yourself. Fortunately, your target audience is very accessible. You can simply jump on the dozens of design related slack channels and post your screeners there. Design comprises of many professions so make sure to post on the right communities. Additionally, meetup groups are also great for recruiting, just make sure you get permission from the moderators to post for you for credibility. Facebook groups, Reddit subreddits, etc are all valid sources.
I'd recommend using your personal network in whatever way you can to get some participants. You can also seek out those types of people through incubators and coworking spaces. There's also a nice article with a lot of creative ways to recruit that I've referred to a few times: https://tsharon.medium.com/43-ways-to-find-participants-for-research-ba4ddcc2255b