I’ve been looking for a table saw recently in the University City area on a student budget. I’ve found plenty of older/vintage saws for a good price, but the lack of a riving knife/self squaring fence makes me leery of them. How much would you he expecting for a decent secondhand table saw? Thanks!
As to table saws, lots to unpack. Old saws can be really good with some TLC; a riving knife can be substituted by a splitter. Self-squaring fence is not a term I’m familiar with for table saws. Fences usually can be adjusted to square. As to price—decent used models probably start at $500, but I’ve seen $100 for old Sears models that with care can be OK—you do get what you pay for! Best advice—shop with someone who knows table saws.
Is there any way to retrofit a riving knife/splitter?
When I meant self squaring, I meant one that doesn’t have to be manually aligned with the blade every time you clamp it down, as I have been told is a common occurrence with most jobsite style saws. I’ve seen a couple of listings that I’ve been trying to barter/buy on craigslist and offerup, but most of them seem to be those jobsite saws.
The student budget is a challenge. There is a Delta unisaw on the Wants and Disposals for $800 as well as another multi use unit. Another avenue may be to buy a new contractor saw and tune it up or forget it and buy a bandsaw. I think that Investing in a Sawstop would be worth every expensive penny. You just can’t get those fingers back!
I would be happy to talk to you but I might convert you to the power-free dark side! Hand tools! 
I used to be a hand tool user, but ripping 8/4 hickory has made me reconsider my life decisions 
That, and I got stood up for 4 hours yesterday trying to get a set of auger bits for my brace