Design an App Mockup

Willing to spend around 30$ for this project Project requirements --------------------------------- need to create a simple level in cartoon style that has 1. 10 different skyscrapers 2. 5 different trees 3. simple stones and flowers and some road and grass...i've attached a mock up for your reference need it to look professional in cartoon style if you have some account in some 3rd party stock - that will be a bonus thank you