There are resources like here that might be able to help:
https
/soldiersangels.org/Laptops-for-Veterans.html
Also, depending on when you served, you might have some GI Bill benefits that could pay for school and a computer for classes:
https

/benefits.va.gov/gibill/
Another source, where you can sometimes find "free to good home" or almost free is Craigslist in your area:
https

/louisville.craigslist.org/