We were using ShowMyPC but that has become more expensive as well.
We are starting to use Skype For Business because presenters can show their screen. Since we're an office 365 shop, everyone here gets S4B as part of their subscription.
Our conference calling system, AT Conference, just reminded me about their web conference platform. It's only $10 per month but they have a 5 license minimum. If you aren't a Skype for Business subscriber, it could be a good deal.
AT Conference. Only $9.99 per month
• Desktop and application sharing
• Webcam video
• File transfer
• Audio integration
• Remote desktop control
• VoIP audio capabilities
• Mobile integration