A few years ago, I sat in on a conference session that featured a panel of podcasting experts. The topic of logos came up, and one of the panelists said something like this:
If you have a $500 podcast budget, spend $450 on the logo.
While that advice demonstrates the importance of a logo, you don't have to spend that much to make one that works. Before you get started, take time to look at great examples of podcast logos.
Your logo needs to be 1400 x 1400 pixels (as a jpg). You could create a blank square of that size and make one of your own using Canva or PicMonkey. Or you can hire someone to (within your budget) to create one for you using services like Fiverr or Upwork.
Or, if I can help you with your logo or any other podcast element...contact me!