So this year I got a $150 tax credit and I'm assuming its because I started my 401k last year but why am I having to use a tax credit?

It sounds like you are referring to the Saver Credit.   If the amount of the credit is so low that you would prefer to skip getting the credit so that you do not have to upgrade to Deluxe, then tell the software that you were a student in 2024.  That will disqualify you for the credit and keep you in the Free Edition.

Or—-Use this IRS site for other ways to file for free.  There are 8  free software versions available from the IRS Free File site

https://apps.irs.gov/app/freeFile/

Or—if you live in certain states you may be eligible to use the new IRS Direct File

In Filing Season 2025, Direct File will be available in Alaska, Arizona, California, Connecticut, Florida, Idaho, Kansas, Maine, Maryland, Massachusetts, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, Oregon, Pennsylvania, South Dakota, Tennessee, Texas, Washington, Wisconsin, and Wyoming. 

https://directfile.irs.gov/

https://home.treasury.gov/news/press-releases/jy2629