currently it is not possible to set up a template with spot instances that does not specify a bid price.
It is possible to create spot requests in EC2 without setting a bid price. This results in a default bid price matching the on-demand price and behaving otherwise same.
This is described here: https://aws.amazon.com/de/blogs/compute/new-amazon-ec2-spot-pricing/
I see here that the used library also shortly mentions the default to be the on-demand price so it is an optional setting: https://docs.aws.amazon.com/AWSJavaSDK/latest/javadoc/com/amazonaws/services/ec2/model/RequestSpotInstancesRequest.html#setSpotPrice-java.lang.String-
Is there any reason why this is not yet possible in this plugin?