I tell everyone that if they can find ME at a better price I’ll match it. But I know my experience from owning and operating retail businesses makes my grasp of UX and post SEO more valuable than some cheapo SEO service.
Know your worth as others have said and once they see your operating levels hopefully they will realise why you are priced your way.
In truth, growth companies that want to win in search have people doing SEO every minute of the day. That means they spend thousands every month, not $75. As if Cadabra (former name of Amazon) got big using a service like that.
Sadly some want to feel like they have ticked the box of doing SEO, even if it does nothing for them.
I would often tell people to check out the $75 service and then come back to me if they are unsatisfied. These days I focus on clients who want to invest in their business, not in delusion.