I've found that avocado oil is really expensive. I've only been able to find it at my local Whole Foods. Haven't checked Trader Joe's, though I'd wager that if they did have it, it'd be a bit less expensive than WF.
Perfect: the next fad superfood.
Check your local Costco, they had some last time I was in. I forgot what it cost but I imagine it's a lot cheaper than Whole Foods.