Reddit mentions of Plano 131250 1312 Ammo Box,OD Green 131250,4.80 x 7.40 x 11.60 inches

Here is an Amazon link

I'm curious if anyone has any ideas on making a foam insert for this

These work well if your bed is raised, but large / extra large BD toys won’t fit. I also use ammo boxes here

Yeah, you're comparing a 5 day food supply to 30 day food supply. Even if we assume the extras are useful, it's not a good deal.

A cursory look on Amazon yields:
9 day worth of SOS Rations, $20.45 (vs 5 days)
Ammo Box, $5.98
100 Aquatabs, $9.90 (vs 10)
10 1-gallon mylar pouches, $8.99 (vs 1 small bag)
Similarly stocked survival tin, $15.50

Now I already have more things and I'm only at around $60.

Plano 1312 Ammo Box https://www.amazon.com/dp/B005IURN5M/ref=cm_sw_r_cp_api_JJWMzbG4T0B5W

Thanks, I got the ammo can from Amazon, here's the link I'm very happy with the quality, especially for the decent price.