Use p2.xlarge instance type and ami-e00a8180 AMI image. Details
Open ports 22 (ssh) and 80 (http) on your freshly created instance,
you create a security group
and attach it your instance to get ports open
Instance you have created contains all you need: fresh versions of theano, lasagne, CUDA driver and cuDNN, just lunch ipython and get hands dirty:
$ sudo su
$ export THEANO_FLAGS='cuda.root=/usr/local/cuda,device=gpu,floatX=float32'
$ export PATH=/usr/local/cuda-8.0/bin${PATH:+:${PATH}}
$ jupyter notebook