How much are you willing to pay? https://renewablelube.com/ mostly plant based for the solar source. In general about 5x the price of pumped oil, and they may not last as long. I've bought for them before, no other relation

Prices of products are a very strong function of total production. Solar panel electricity once was 20x the price of other ways - now its 0.5x or less. In competitive industries the price will come down to only a small multiplier on raw input price.