How long does this keep once opened?

Depends on your appetite for awesome tasting mayo. At company headquarters, not too long! We recommend you consume within 60 days of opening.

Is this Mayo Whole30 approved?

Hi! We have been Whole 30 approved since 2016! Please check out this link for all information including certifications and ingredients https://www.primalblueprint.com/primal-kitchen/chipotle-lime-mayo-single-jar/. Our mayo has made some great strides and now you can enjoy all the great benefits with amazing taste!

is it really $18 for one jar, as it says above? I'm hoping that's a typo. I can get it in a local store for 10 or on Thrive for 8. so what's the deal?

That is the price for one jar, from another seller, not Wild Mountain Paleo Market. We have more stock coming to prime soon and the price will be lower. Until then you can buy our direct listing which is $9.95 and about $5.75 shipping. You save more as you add jars, or try the multi jar packs for even more savings.