Here’s my little beginner bog that I made last year. I live in MI zone 6b ish and wasn’t sure how I was going to need to overwinter them yet so I used a small plastic bucket to actually plant in, then put that in a bigger pot. The idea was that I could lift out the plastic bucket and move it to the garage for winter if I had to. The bucket is just over 10” wide and about 2 gallons. I drilled some holes a few inches below the rim for drainage.
There is space between the rim of the bucket and the big pot that I put blue-eyed grass in this year and top dressed with moss to mostly hide the plastic. The sarracenia will outgrow it for sure but that’s a problem for later.
I highly recommend starting cheap and small and learning what works for your space and climate. Much easier to make adjustments if you aren’t dealing with something huge and complicated!