batting alternative for cushion cover?

Hi! I've been sewing casually since I was a child, and have been wanting to pick it back up again, and I became interested in quilting. I'd like to make a quilted cushion cover and found some guidance on how to make it.

I don't have any batting and since I wouldn't need a lot of batting since a cushion is quite small, I'm wondering if there is a different alternative I could use which would be more sustainable and cost effective?

Also a small side point, but I also don't have basting spray, do you think I could get away with pinning or thread basting for this project?

Thank you so much, this community looks wonderful and I'm really looking forward to extending my sewing skills!!