Hey Lee,
I am only starting out, not sure what you mean by DIYn one, seems complicated?

I'd like to buy ready made so its ready to go for a beginner.

I was thinking 40w C02 for now maybe as anymore wattage seems much more expensive for a beginner.300x200mm seems ok to start with as larger seem more expensive starting out. I could upgrade in the future.

I'm just going to practice with small boxes plans I've seen online so nothing too thick.
Maybe 5mm to 1/4 inch thick?

Workload will not be too strenuous as I will only be playing around getting at first used to using plans on lightburn or whatever software and cuts.
Any recommendations or suggestions based on the info above

Patrick