Thoughts on nordictrack t 6.5 s treadmill?

I'm trying to lose weight with low impact daily walking due to tendinitis in my knees. I'm looking for something to place in my living room. I'm pretty much a beginner with treadmills so I'm looking for some feedback. Also, is $400 used good for this treadmill? Seems to be the average price on Facebook marketplace. Thanks in advance.