I know this thread is a bit dated, but hey, better late than never, right? If you're still in the market for a 3rd party marketing platform, I've got a cool suggestion for you. Forget about Purple (old news, my friend) and check out https://www.searchseo.io/gmb/.
They've got all the bells and whistles you need to show ads to your clients. Picture this: captivating captive portals and seamless ad placements during regular browsing. It's a win-win situation!
Don't waste another minute, buddy. Head over to their website and see what they've got to offer. It's time to shake things up and take your marketing game to the next level.