I’ve taken to starting my seeds in cake pans - I got four big ones, with the plastic lids, from the dollar store for about $5.
I did something similar for a while. But a few years ago, I switched over to using a clear plastic tote where the lid acts as a seed starting tray and the tote becomes a mini-greenhouse...
The tote lid is much stronger than a standard 10X20 seed starting tray, plus you get the option of using the tote as a mini-greenhouse which I use in the early springtime.
I used toilet paper rolls to make ‘cells,’ those are free with paid purchase of toilet paper,

and squeezed in 35 per tray.
I did not have luck with using toilet paper rolls for seed starting. Well, actually, the seeds started OK but you have to transplant and/or up pot them fairly soon. If not, the plant will grow too large and become root bound. Also, I had a problem with the paper rolls staying too wet and I got mold growing on my paper roll pots. I lost most of them due to the mold.

I am not the best gardener. You may have better results.
What did work for me was buying
3-inch net cups that can be reused year after year...
I was able to start and grow my pepper and tomatoes in those net cups for 8 weeks with no problems. The net cups are bigger than a toilet paper roll pot, but you don't have to worry about up potting the plant before transplanting. They do take more potting soil initially, but in the end, I think you would have to up pot from the smaller toilet roll pots anyway. Well, if you grow the plants for 8 weeks like I do.
Also, because of the slits, the soil drys out in the air and did grow mold. I bottom water the net cups sitting in the tote lid and let the potting soil soak up the water. If I overwater the plants, all I have to do is lift the cups out of the water and let them drain out for a few hours.
And I’m not dealing with the stupid plastic netting on the coco fiber pellets choking off my seedlings’ roots!
One of the best aspects of using those net cups is that they have slits all around the cup. That will air prune the roots when they reach the air, they grow additional new roots, instead of circling around the pot and causing the plant to get root bound. When you transplant it, it is much healthier, and the roots are ready to branch out.
I'm not saying the net cups are the best system for seed starting, but for me, I only had to make the initial purchase of supplies and can reuse them year after year. I have had much better results with the net cups than other methods I have tried. All things considered, I believe I am saving money, time and labor, by using the net cups and the clear plastic totes as my seed starting trays and mini greenhouses.