Since it is just creating machines for you (i.e., it's created under your DigitalOcean account) can't you just stop paying for forge after you've created your servers, and keep using your DO account normally.
Well, you could. But you do get other features such easy management of env. variables, scheduling, New Relic monitoring and network handling.
Even if you are just running 2 sites, I really do think this is a great value for money ($10). If they only (as I wrote in my other comment) allowed for alternative ways to push your code.