You can probably buy a 2-3 year old hp or Dell desktop computer used for $150 or less and a medium sized screen for $125 off your local Craigslist. SEE IF YOU CAN GET THE DOCs that came it. If it has WDOs 7 it will relentlessly ask you to upgrade to W10, which I have not done, nor do I plan to. It may make no difference to you.
I got a 25 inch HP screen from Best Buy for $129 plus sales tax. I wouldn't risk a Craigslist transaction to save $4.00. And I got it new in the box with cables instead of the risk of receiving stolen property.
Speaking of $129, and Dells, one can buy a new Dell (bottom of the line Intel Core 2 Duo Processor 3.0GHz Microsoft Windows 7 Professional 64-bit 4GB RAM ) for that price at Microcenter. (Win7 Professional)