I'm also looking for a better answer to this. I'm building a website for my mom to sell her jewelry, and for her necklaces, the chains are an add-on that you can buy along with her pendants. What I ended up doing was creating a separate, unlisted product for each chain and linked to it from the appropriate pendant page (saying "this listing is for the pendant only - if you'd also like the chain, click here" and having that take you to a listing for the chain only, but pictured with the pendant again as the chains are curated to each pendant). It's not ideal but it's better than accidentally selling two of a one-of-a-kind pendant or listing the relatively inexpensive chain alongside the expensive pendant and having the listing show the lower price.
I'm definitely interested if anyone has a more streamlined way, to include an 'add-on' type lower priced item directly in the listing without the listing showing the price of that lower item as a "priced from ___" on the main page.