1991 honda accord will not stay running unless you keep slight pressure on the key. I was told the problem maybe the ignition switch. Estimate given for repair was 180.00. What should I DO?

Replace the switch.

It's an easy job to replace the ignition switch yourself:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-2.html#post224652