Any recommendations for getting the cheapest price on preservative free eye drops?

I normally buy olopatadine but it's super expensive ($10 for a 5 ml bottle of generic 0.1%) and it seems like it has BAK preservative in the US. I once bought Olopat solution from India which states on the bottle that it's BAK free but it's even more expensive.

I see that they recently came out with Alaway (Ketitofen) preservative free but dang those prices.