Silly question: Maternity’s Clothes

I’ve fought off wearing maternity clothes for the longest time (other than one pair of sleep shorts and they’re so damn comfy) I just don’t want to spend a lot of money on clothes I’ll only wear on a few occasions and I don’t plan on having another baby for a few years so it just hasn’t seemed necessary but it’s at the point where basically all of my clothes are uncomfortable and my jeans don’t button. I’m not lying when I say nowhere within 2 hours of me sells maternity clothes so I plan to order some online but this is my question, do you size up? Or do you just order whatever your usual size is? I know some stuff will be a by fit basis but I’m just curious where to start in that aspect. Also any recommendations on where to get affordable prices?