Best RCA interconnect up to ~$100?

SVS rca interconnects --> warm/thick sound with admirable detail retrieval/noise mitigation (same goes for their speaker cables, xlrs, etc)...There is no beating SVS cables on a 100 dollar budget if you like that type of sound.

If you’re just starting out, my advice is to buy a pair of ICs from Blue Jeans cable and listen for a year. Then you can try something more expensive and see if it makes a difference in your system. Blue Jeans is very solid entry-level stuff. If you have to spend more, I would look at Audioquest. They have cables at all price points, so just find whatever they are selling in the $100 range. I really wouldn’t agonize over this at this point. But I still think Blue Jeans will give you a very solid foundation. 

DH labs silver sonic.  Just above your target but worth it. 

Jerry