Adobe Creative Cloud is the standard for creative software from photography to art to web design.  The Cloud includes Photoshop, Illustrator, Dreamweaver, and many other familiar titles.  The price for purchasing the whole suite of software offered by Adobe was prohibitive for teachers until Adobe switched to the subscription model and offered a generous 60% off to teachers and students.  All you need to do to get the discount is provide your school name and your school email account as evidence of affiliation.  The cost is about $20 per month.  Check it out at the Adobe website. Admins interested in institutional licenses can learn more here.

Full disclosure:  I am NOT an affiliate and have no connection with Adobe other than as a long-time customer.