Honestly, I should keep better track. But..
Travel $0 I work the auctions in to trips to that area for my other business. I try not to buy lockers that won't fit in my full size van. Been known to sell items to others that wanted one item from the locker on site.
Dump runs $60 a ton. I avoid them as much as I can. I pay 100 a month for the 3 yard dumpster behind my shop. I use that as much as possible. tipped once a week.
Storage? I turn and burn on a lot of items I buy. IE, I dump clothing on CL in lots, I find i do better asking $50 for a tote bin of infant clothing than trying to price it and list it outfit by outfit. Might make more, but it's much easier to lay it all out, snap a photo and list it as a lot. I'll price large items 10-25% less than others on CL to move them quickly.
When I do need to store something I keep it in the basement of my business. I pay $100 a month for the 1500 square foot basement. (Inaccessible except through my shop. but he wanted "something" for it) but a good 50% of that is unrelated to storage lockers down there.
I should mention I am a bit like Berry in the show. I buy looking for things I want to keep. I always want to make money on the locker. Thankfully the items I keep tend to be items no one wants anyways