Need Advice on buying a Chromebook for College

Hey r/chromeos, Zigziggy7 here. I've been a lurker for a while now, and have decided on getting a chromebook for college next year. I'm a senior in highschool, and will be using my desktop and the school PCs scattered around campus for AutoCad and heavy computing needs, and just needed a notetaking light laptop with a really good battery. Also having a decent screen for netflix and browsing, the ability to swap into bigger ssd, and eventually getting linux to play some Steam games brought me to the Dell Chromebook 13 4gb celeron or i3 (haven't made up my mind yet). I liked it better than the shoddy quality of the Toshiba CB2, and that the Dell would probably get me through 4 years of college without breaking.

My problem is I've never owned one before, and although I'm pretty sure I'd like it, it's hard justifying the price for something that doesn't offer everything. I'm thinking about buying an inexpensive Chromebook off of ebay, craigslist, or something cheap under $100 (the lower the better) just to try out the Chrome OS. Then if I liked it I'd buy the Dell 13.

Is this a good idea? Is the Dell a solid choice? Any recommendations on a cheap Chromebook that would help me test the waters?

Here's the local Craigslist listings if that helps https://stlouis.craigslist.org/search/sss?sort=rel&query=chromebook

Thanks in advance! Zigziggy7