Kubernetes engine on DO is a great way to have a personal Kubernetes cluster for experiments and small side projects. A single node Kubernetes Cluster costs around 10$/month, which is a very acceptable price.
But when you create an Ingress controller in your cluster, even if you only have one node, DO automatically creates a load balancer. This makes the price double to 20$/month.
While the extra 10$ for the Load balancer is not significant for companies, for personal projects, paying that extra is too much.
Also its not clear in the documentation that you need a Load balancer when using Kubernetes Engine.
I think the best would be to include a single free Load Balancer in the Kubernetes Engine offer. It could even be something like, you only pay for load balancer if you have more than 3 nodes in your cluster for example.
A more limited solution would be not automatically create a Load balancer for single node clusters and let Kubernetes ingress do all the work.
I would prefer the first option as it allows more flexibility as you could have some little bigger clusters but small engouh. (less than 3 nodes).