Routine with "bulk" items

I would really like to start taking better care of my skin, but the thing that always stops me is when I run out of a product. I really want to find some good skin care products that I can get a lot of at one time. When I say "bulk" I don't me like 2 gallons of the stuff, but I just want to steer away from getting tiny little bottles that cost $30.

Things I am missing from my face routine are a good sunscreen, retenoid and vitamin c serums. I have a cleanser and moisturizer that work for me that I can buy in large quantities.

Can y'all please help me simplify this skincare stuff, it's something I can tell is important and want to do right, but don't want to over complicate it