If I actually paid myself fairly for my time, these would probably cost at least $20 without a strap and at least $30-40 with one (a full length strap honestly takes longer than the holder itself because of the technique I use to make it strong and comfortable). However, I honestly just enjoy crocheting and I will be crocheting something regardless, so I don't really care about being paid in full. So, I'm willing to offer a "pay what you want/can" price instead, with a low-end recommended price of $15 without a strap and $22 with (you can still pay more or less than this). You'll be paying after it's complete, so I'll provide information on how much time I spent making your specific water bottle holder and how much the yarn cost so you can use that to inform your payment. One water bottle holder typically only uses one ball of yarn, so if you wanted any customizations that entale multiple yarns, that'll increase the cost by a few dollars.