Best RCA interconnect up to ~$100?

If you go DH Labs, buy bulk.

I made a two foot pair of Pro Studios with AECO silvers for less than a hunski.

DH Labs has an eBay store.

Pine Tree Audio.  Well made available in a variety of colors.  Good insulation, OCC copper, quality connectors.  That's all I use in my system.  Power cords also.  Very quiet, neutral and good sound staging.  You will not need new ones. IMO

My vote would be to skip the Blue Jeans, this coming from someone who used them exclusively for my first six years or so with this hobby. In the end I discovered they don’t scale up very well from entry level, and better options in comparison reveal them to be a little grainy and bass shy.

The Mogami 2497 is $100 for 3 feet and is superb, would recommend wholeheartedly. Transparent, uncolored, neutral sound, with better high frequency extension than BJC, and much better mids and bass with a wider soundstage. They aren’t as good as Transparent in my system, but hold their own considering the reasonable cost.

like this one @nixanthrope ?

https://www.amazon.com/Foot-Audiophile-High-Definition-Interconnect-Connectors/dp/B01EL1MO0C/ref=pd_lpo_sccl_2/137-8607880-5880906?pd_rd_w=5JSRU&content-id=amzn1.sym.116f529c-aa4d-4763-b2b6-4d614ec7dc00&pf_rd_p=116f529c-aa4d-4763-b2b6-4d614ec7dc00&pf_rd_r=922Q3DWAWQ4N8K2Y387W&pd_rd_wg=mPXdj&pd_rd_r=5f2d05bf-7de6-4056-9b78-d85b9b14f245&pd_rd_i=B01EL1MO0C&psc=1