Why is it making me upgrade to file taxes and charging $90??

Well you never have to upgrade to any of the LIVE options  but when you get to a place the FREE version doesn't cover you will be required to upgrade to continue. 

Free Edition is for simple returns that file a 1040 with no additional schedules, and is free as long as you don't select any add-ons or upgrades.

Review your fees to find out why you're being charged. Then, follow the directions to remove any unwanted charge:

• Remove PLUS Help & Support
• Remove Pay With Your Refund
• Remove Premium Services Benefits
• Remove MAX Defend & Restore
• Remove a state
• Clear and start overto remove all fees and start from scratch.

Related Information:

• Can I downgrade to a lower-priced version of TurboTax Online?
• What's included in PLUS Help & Support?

If you qualify to use it, there is another full-featured free version of the software:

Try Free File: 

You qualify if your income was $36,000 or less,

or $69,000 or less if active duty military,

or if you qualify for Earned Income Credit

https://ttlc.intuit.com/questions/1900583-what-is-turbotax-free-file-program

If you switch to Free File you must create a new account and new user ID.

https://ttlc.intuit.com/questions/2026912-how-do-i-switch-to-turbotax-free-file-program