I do digital advertising for tech companies as well as "learn to code bootcamps" etc. IMHO Adwords is overpriced. You're much better served by Facebook or Twitter. The social context is likely key for a play like this. I would also tend to stay away from Linkedin based on price. Although if your ltv per customer is high enough, it may make sense. Feel free to shoot me an email if you'd like to chat about it. I'm always happy to give out free advice.