Swapped my weights for water bottles last year and never looked back. I use old detergent containers filled with sand for extra weight, and they're perfect for lunges. The grip on those handles is surprisingly sturdy, and I can adjust the sand level for different exercises. My favorite trick is using a duffel bag packed with cans for goblet squats, which really challenges my stability. It's so much more engaging than staring at a rack of identical dumbbells, and I feel like I'm actually using my brain along with my muscles. Plus, the cost savings let me splurge on other stuff, like better workout shoes.