I had mold with both the home made paper pots and toilet paper pots.Although there are issues with plastics, I've had bad experiences with cardboard planters and mold in the past.
Now I use large yogurt or cottage cheese cartons to make pots. Eventually the plastic gets brittle, but I have some pots that are 3-4 years old. I've posted my how to a few times; I don't know if I've put it here, so I'll go ahead and post it again.
Collect this kind of container, with the lid.
Cut the bottom off.
This is your pot. Poke holes in the bottom (lid) for drainage.
Fill with soil, plant your seeds, grow a happy little plant. When it's time to set it out in the garden (after hardening off), dig the hole, take the lid off the bottom, and set the pot in the hole. The taper of the container will let you slide the pot up off the dirt and plant.
Wash, sterilize with a bit of bleach in the rinse, dry, and use again the next year.