I used Adobe Photoshop previously for creating mocks. The current project sponsor suggests Corel PaintShop Pro instead. I couldn't find any info for creating mocks from the scratch using this tool. Can you please suggest if Corel Paintshop Pro is a good option and point me to any tutorials that can help me get started. Thank you.
You should use the application which you can master the most. Be it Microsoft Excel, Balsamiq, Photoshop, Corel Draw or Corel Paintshop Pro. But be sure to make the outcome look like muckups so you don't confuse your stakeholders that you've already built the application. If a mockup look too good, you will have less chance to get the hours you need for implementation.