Non-Standard Miter Slots - This one is a downer. One of the primary advantages of having a table saw is access to jigs that expand the saws functionality. This is a major issue if you plan on buying after market jigs. Given that we are limiting the cost of this buildout to $500, I am guessing that after market jigs are probably low on the priority list. Your going to want jigs once you start researching what they enable you to do, my advice is to build your own - there are plenty of plans online.
I wouldn’t give up on Craigslist or garage sales.. For around $1K or less, you can pretty easily find the four big ticket items (TS, BS, Jointer and Planer) and have the extra $2K to spend on accessories, material, DC, other goodies, etc. The key is patience and persistence, and if applied correctly, you can have a fantastic setup for very little compared to purchasing new. If you are setting up a business, you don’t usually have the time to scour for good deals, but for a personal shop, there is no pressing need other than that itch to get something done.