HAYStraws! Are my absolute favorite straw eco option. Very low-cost production (its hay), paper packaging, come in different sizes and this company is awesome to work with. They deserve all the support they can get!
Oh, and the purchase is cheapest on the HAYStraw! website, NOT on Amazon.

Stainless Steel Drinking Straws & Cleaning Brush –

Set of 10 Long Bamboo Straws With 2 Cleaning Brushes and a Cotton Pouch –